Cover

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

Contents — 14 sections
  1. Section 1
  2. Section 2
  3. Preface
  4. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  5. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  6. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  7. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  8. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  9. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  10. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  11. 8. Protective Circuits
  12. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
  13. 10. Tables
  14. Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Beru
Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
(introduction...)
Preface
1. Selected Graphical Symbols of Electrotechnology
1.1. Graphical Symbols for General Circuit Elements
1.2. Graphical Symbols for Types of Current, Voltage and Connections
1.3. Graphical Symbols for Lines and Line Connections
1.4. Graphical Symbols for Resistors
1.5. Graphical Symbols for Capacitors
1.6. Graphical Symbols for Coils and Transformers
1.7. Graphical Symbols for Current and Voltage Transformers
1.8. Graphical Symbols for Electrochemical and Electrothermal Sources
1.9. Graphical Symbols for Tubes
1.10. Graphical Symbols for Semiconductors
1.11. Graphical Symbols for Switching Devices
1.12. Graphical Symbols for Machines
1.13. Graphical Symbols for Meter Movements and Measuring Instruments
1.14. Graphical Symbols of Electroacoustics
1.15. Graphical Symbols for Wiring Plans
2. Bell Circuits
(introduction...)
2.1. Direct-current Bell
2.2. Alternating-current Bell
2.3. House Bell Installation
2.4. Alarm Systems
3. Basic Circuits of Illumination Engineering
3.1. Circuit-breaking Arrangements
3.2. Series Circuits
3.3. Two-way Switching Circuits
3.4. Staircase Lighting Circuits
3.5. Fluorescent Lamp Circuits
4. Electrical Machines
(introduction...)
4.1. Direct-current Machines
4.1.1. Direct-current Generators
4.1.2. Direct-current Motors
4.2. Three-phase Machines
4.2.1. Three-phase Generators
4.2.2. Three-phase Motors
4.3. Transformers
4.3.1. Single-phase Transformers
4.3.2. Three-phase Transformers
5. Contactor Circuits
5.1. Types of Excitation of the Control
5.2. Possibilities of Representing Contactor Circuits
5.3. Reversing Contactor Circuits
5.4. Arc Extinguishing Circuits
5.5. Three-contactor Star-delta Connection
5.6. Squirrel-cage Induction Motor
5.7. Sliping Rotor
5.8. Interference Suppression
5.9. Light-current Controlled Power Plant with Impulse Relay
6. Rectifier Circuits
6.1. Rectifier Circuits of Alternating Current
6.2. Rectifier Circuits of Three-phase Current
7. Measurement Circuits
7.1. Measurement Circuits in Direct-current Installations
7.2. Measurement Circuits in Alternating-current Installations
7.3. Measurement Circuits in Three-phase Installations
8. Protective Circuits
9. Circuits in Motor Vehicles
(introduction...)
9.1. Battery Charge
9.2. Ignition Systems
9.3. Starting Aid for Diesel Engines
9.4. Turn-signal Flasher
10. Tables
11. Basic symbols and formulas of electrical engineering
(introduction...)
11.1. General direct current engineering
11.2. Magnetic field
11.3. Law of induction
11.4. Electric field
11.5. Alternating current engineering
11.6. Calculation of power
Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
(introduction...)
Preface
1. Selected Graphical Symbols of Electrotechnology
2. Bell Circuits
3. Basic Circuits of Illumination Engineering
4. Electrical Machines
5. Contactor Circuits
6. Rectifier Circuits
7. Measurement Circuits
8. Protective Circuits
9. Circuits in Motor Vehicles
10. Tables
11. Basic symbols and formulas of electrical engineering

CRYSTAL

Lehr- und Lernmittel,
Informationen, Beratung

Educational Aids
Literature, Consulting

Moyens didactiques,
Informations, Service-conseil

Material did�ctico,
Informaciones, Asesor�a

Feedback IBE e.V.

GTZ - Deutsche Gesellschaft f�r
Technische Zusammenarbeit (GTZ) GmbH

Textbook for Vocational Training

Institut f�r berufliche Entwicklung e.V.

Berlin

Original title:
“Schaltungen, Formeln, Tabellen - Elektrotechnik”

Author: Klaus Janoske

First Edition © IBE

Institut f�r berufliche Entwicklung e.V.
Parkstra�e 23
13187 Berlin

Order No.: 91-34-0101/2

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
(introduction...)
Preface
1. Selected Graphical Symbols of Electrotechnology
2. Bell Circuits
3. Basic Circuits of Illumination Engineering
4. Electrical Machines
5. Contactor Circuits
6. Rectifier Circuits
7. Measurement Circuits
8. Protective Circuits
9. Circuits in Motor Vehicles
10. Tables
11. Basic symbols and formulas of electrical engineering

Preface

This Textbook is intended for all trainees in the field of electrotechnology. It contains the more important circuit diagrams and formulas and a limited number of selected tables of direct-current and alternating-current engineering.

With the help of this Textbook, the trainee will be in a position to read and interpret electrical wiring and circuit diagrams in order to perform his job according to the rules of good workmanship. At the same time, the trainee is encouraged to prepare and draw circuit diagrams without assistance and to use graphical symbols correctly.

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
1. Selected Graphical Symbols of Electrotechnology
1.1. Graphical Symbols for General Circuit Elements
1.2. Graphical Symbols for Types of Current, Voltage and Connections
1.3. Graphical Symbols for Lines and Line Connections
1.4. Graphical Symbols for Resistors
1.5. Graphical Symbols for Capacitors
1.6. Graphical Symbols for Coils and Transformers
1.7. Graphical Symbols for Current and Voltage Transformers
1.8. Graphical Symbols for Electrochemical and Electrothermal Sources
1.9. Graphical Symbols for Tubes
1.10. Graphical Symbols for Semiconductors
1.11. Graphical Symbols for Switching Devices
1.12. Graphical Symbols for Machines
1.13. Graphical Symbols for Meter Movements and Measuring Instruments
1.14. Graphical Symbols of Electroacoustics
1.15. Graphical Symbols for Wiring Plans

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

1. Selected Graphical Symbols of Electrotechnology

1.1. Graphical Symbols for General Circuit Elements

Term

Graphical Symbol


in full

simplified

Polarity



positive

+


negative

-


centre point, neutral

N


Directions of transmission and motion



energy direction


direction of motion


sense of rotation (rotating)


direction of turning


Possibilities of adjusting, setting



adjusting


setting


Variabilities



general, linear


non-linear


Pulse shapes



rectangular pulse, positive


rectangular pulse, negative


Shieldings



general

- - - -


electrostatic


electromagnetic


shielding of a component


1.2. Graphical Symbols for Types of Current, Voltage and Connections

Term

Graphical Symbol


in full

simplified

Type of voltage and current



direct voltage


direct current



alternating voltage, alternating current


alternating voltage within the range of audio frequency


alternating voltage within the range of high frequency


direct or alternating voltage


Alternating current connections



star connection


delta connection


star-delta connection


zig-zag connection


1.3. Graphical Symbols for Lines and Line Connections

Term

Graphical Symbol


in full

simplified

Lines



line, general


2 lines

3 lines

4 lines

n - lines


crossing of two lines without connection

crossing of two lines with connection

shielded line

coaxial line


Line and cable connections



earth connection


ground connection (chassis or the like)


disconnectable and non-disconnectable electrical connection, general


disconnectable electrical connection, e.g. terminal


cable termination


coupling sleeve


joint box for a branching


joint box for two branchings


1.4. Graphical Symbols for Resistors

Term

Graphical Symbol


in full

simplified

resistor, general


resistor, variable, with possible circuit interruption


resistor, variable, without circuit interruption


resistor as voltage divider


resistor, adjustable

resistor, infinitely variable resistor, voltage-dependent non-linear

fusible cut-out, general


potential fuse, general


two-electrode arrester


ion arrester (dot = gas filing)


1.5. Graphical Symbols for Capacitors

Term

Graphical Symbol


in full

simplified

capacitor, general


electrolyte capacitors



polarised


non-polarised


lead-in capacitor, polarised


lead-in capacitor, non-polarised


variable capacitor


variable capacitor with indication of rotor


anti-interference capacitor


1.6. Graphical Symbols for Coils and Transformers

Term

Graphical Symbol


in full

simplified

Coils



general



or


air-cored coil



or


air-cored coil with two tappings

or


iron core


iron core and air gap


iron dust core


iron-core choke

or

Transformers



single-phase transformer with iron core (if errors cannot be made, the core need not be drawn)



single-phase transformer with iron-core and 3 windings (core not represented)

three-phase transformer in star-star connection (core not represented)

three-phase transformer, star-delta connection

three-phase autotransformer in star connection

1.7. Graphical Symbols for Current and Voltage Transformers

Term

Graphical Symbol


in full

simplified

Current transformers



primary winding

or


secondary winding

or


current transformer, general

Voltage transformers



general

or

capacitive

or


1.8. Graphical Symbols for Electrochemical and Electrothermal Sources

Term

Graphical Symbol


in full

simplified

battery cell, general


battery, 5 cells with one tapping


thermoelectric element


1.9. Graphical Symbols for Tubes

Term

Graphical Symbol


in full

simplified

diode, indirectly heated


duodiode, indirectly heated

or


triode, indirectly heated

or


duotriode with separated cathodes, indirectly heated, heating filament with central tapping, internal screening of the system


tetrode


pentode, suppressor grid connected with cathode


triode - pentode


triode - heptode (according to the circuit, the systems may be drawn left-and-right reversed)


1.10. Graphical Symbols for Semiconductors

Term

Graphical Symbol


in full

simplified

Transistors



point contact transistor or junction transistor, type p-n-p


n-p-n transistor


Semiconductor diodes



diode with rectifying function

or


capacity diode


tunnel diode


avalanche rectifier diode


avalanche rectifier diode with avalanche effect in both directions


backward diode


Thyristors



general


backward blocking


backward conducting


n-type gate, controlled at anode side


p-type gate, controlled at cathode side


Semiconductor elements which can be influenced by light



photoresistance cell


photodiode


photocell with depletion layer


phototriode p-n-p


switching diode p-n-p-n


Semiconductor circuits



switching diode p-n-p-n


semiconductor valves in bridge connection


or

1.11. Graphical Symbols for Switching Devices

Term

Graphical Symbol


in full

simplified

Switching members



make contacts, general

break contacts, general

change-over switch, general


change-over switch with central rest position


Relay switching members



make contacts

break contacts

change-over switch with interruption in switching

Switches



hand-actuated lever switch


make contacts with automatic resetting

break contacts with automatic resetting


disconnecting switch, three-pole


power circuit-breaker, three-pole

power breaker, three-pole


power switch, three-pole

switch, three-pole, with one make contact and two break contacts

Drive members



drive, general


drive, thermal


drive by centrifugal force


drive by piston


drive by electrical motor


drive by cams


drive by float


manual drive


manual drive with automatic resetting


foot drive


actuation by means of a key


drive by relay or contactor


Electrical drive systems



relay winding only for alternating current


winding of a relay insensitive to alternating current


winding of an electro-thermal relay


winding of a remanence relay


winding of a polarised relay


winding for relay tripping by over-current

winding for relay tripping by undercurrent

winding for relay tripping by reverse current

winding for relay tripping by overvoltage

winding for relay tripping by undervoltage

winding for relay tripping by error voltage

winding for thermal tripping of relay

relay winding with delay of attraction


relay winding with delay of dropping


relay winding with delay of attraction and dropping


relay winding with electrothermal delay


relay winding with electronic delay


winding for relay tripping by open-circuit working


winding for relay tripping by closed-circuit working


winding for relay tripping by overcurrent with time lag


Plugged connections



receptacle


plug


connector, single-pole


connector, four-pole


h.f. coaxial receptacle


h.f. coaxial connector


h.f. coaxial connector, two - core


1.12. Graphical Symbols for Machines

Term

Graphical Symbol


in full

simplified

rotor with winding, commutator and brushes


asynchronous machine, stator in delta connection, rotor in star connection


direct-current generator

direct-current motor

three-phase generator

three-phase motor (cage rotor)

three-phase motor (slip-ring rotor)

1.13. Graphical Symbols for Meter Movements and Measuring Instruments

Term

Graphical Symbol


in full

simplified

voltage path of a movement

or


current path of a movement

or


movement of a wattmeter


voltage paths for summation or differentiation


current paths for summation or differentiation


movement of a two-phase wattmeter with 2 elements


movement of an ohmmeter


movement of a frequency meter


Measuring instruments



voltmeter

ammeter

wattmeter with 2 elements

electrometer


1.14. Graphical Symbols of Electroacoustics

Term

Graphical Symbol


in full

simplified

Devices



telephone receiver


or

microphone


or

throat microphone


hand set


loudspeaker


or

monohead, general


stereohead, general


record head, mechanical


replay head, mechanical


magnetic head, general


recording head


playback head


magnetic head for recording and playback


erasing head


bell, general


alternating current bell


direct current bell


single-stroke bell


buzzer


horn


siren


howler


Signs



electromagnetic


electrodynamic by coil


electrodynamic by band


piezoelectric


magnetostrictive


capacitive


carbon


Examples



electromagnetic telephone receiver


carbon microphone


capacitor microphone


magnetostrictive loudspeaker


1.15. Graphical Symbols for Wiring Plans

Term

Graphical Symbol


in full

simplified

distribution box

cut-out, single-pole

cut-out, two-pole

cut-out, three-pole

group switch, single-pole


multi-circuit switch, single-pole

single-pole double-throw switch

four-way switch, single-pole

plug socket, single


plug socket, double


plug socket with protective contact, single

plug socket with protective contact, double


luminous key switch


glow lamp


fluorescent lamp

glow igniter


door opener


Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
2. Bell Circuits
(introduction...)
2.1. Direct-current Bell
2.2. Alternating-current Bell
2.3. House Bell Installation
2.4. Alarm Systems

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

2. Bell Circuits

The reference letters and numbers in the illustrations of bell circuits have the following meanings:

a

switch

E

voltage source

b

control switch

f

transducer

c

contactor

g

measuring instrument

d

auxiliary contactor, relay

h

visual and audio alarm

e

protective device

Tr

transformer

2.1. Direct-current Bell


Direct-current bell to be actuated from one place


Direct-current bell to be actuated from two places


Bell installation for reciprocal calls


Sell installation for reciprocal calls with key change-over switch


Bell installation for reciprocal calls with switch-on push-button, line-saving


Bell installation for reciprocal calls, line-saving

2.2. Alternating-current Bell


Alternating-current bell with bell transformer, simple circuit


Bell installation with change-over switch

2.3. House Bell Installation


Circuit of a house bell installation


Circuit of a house bell installation with electric door operator

2.4. Alarm Systems


Circuit of an alarm system with normally open contacts b1 test key, 1 glass panel


Circuit of an alarm system with normally closed contacts b2 test key, 1 glass panel

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
3. Basic Circuits of Illumination Engineering
3.1. Circuit-breaking Arrangements
3.2. Series Circuits
3.3. Two-way Switching Circuits
3.4. Staircase Lighting Circuits
3.5. Fluorescent Lamp Circuits

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

3. Basic Circuits of Illumination Engineering

3.1. Circuit-breaking Arrangements


cut-out, schematic diagram (all-pole)


cut-out, schematic diagram (single-pole)


plug socket with protective contact (all-pole)


plug socket with protective contact (single-pole)


plug socket with protective contact and separate protective conductor (all-pole)


plug socket with protective contact and separate protective conductor (single-pole)


Cut-cuts with plug socket (all-pole)


Cut-cuts with plug socket (single-pole)


two-pole cut-out (all-pole)


two-pole cut-out (single-pole)


three-pole cut-out (all-pole)


three-pole cut-out (single-pole)

3.2. Series Circuits


multi-circuit switch -also know as series switch-, schematic diagram (all-pole)


multi-circuit switch -also know as series switch-, schematic diagram (single-pole)


series switch with plug socket (all-pole)


series switch with plug socket (single-pole)

3.3. Two-way Switching Circuits


two-way switch, schematic diagram (all-pole)


two-way switch, schematic diagram (single-pole)


two-way switch with plug socket (all-pole)


two-way switch with plug socket (single-pole)


two-way switch, economy circuit, schematic diagram (all-pole)


two-way switch, economy circuit, schematic diagram (single-pole)


two-way switch with four-way switch, schematic diagram (all-pole)


two-way switch with four-way switch, schematic diagram (single-pole)


two-way switch with four-way switch (all-pole)


two-way switch with four-way switch (single-pole)

3.4. Staircase Lighting Circuits


staircase lighting circuit with four-way switch (all-pole)


staircase lighting circuit with four-way switch (single-pole)


staircase lighting circuit with four-way switch (switch positions)


staircase circuit with automatic unit (all-pole)


staircase circuit with automatic unit (single-pole)

t = automatic staircase lighting switch unit

3.5. Fluorescent Lamp Circuits


fluorescent lamp at single-phase mains (single-pole)


fluorescent lamp at single-phase mains (all-pole)


fluorescent lamp in lead-lag connection (single-pole)


fluorescent lamp in lead-lag connection (all-pole)


fluorescent lamp at three-phase mains (all-pole)


fluorescent lamp at three-phase mains (single-pole)

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
4. Electrical Machines
(introduction...)
4.1. Direct-current Machines
4.1.1. Direct-current Generators
4.1.2. Direct-current Motors
4.2. Three-phase Machines
4.2.1. Three-phase Generators
4.2.2. Three-phase Motors
4.3. Transformers
4.3.1. Single-phase Transformers
4.3.2. Three-phase Transformers

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

4. Electrical Machines

Designation of electrical conductors

Alternating current



any external conductor

L


1st external conductor

L1


2nd external conductor

L2


3rd external conductor

L3


neutral conductor without the function of a protective conductor

N

Direct current



any external conductor

L


positive external conductor

L+


negative external conductor

L-


central conductor without the function of a protective conductor

M

4.1. Direct-current Machines

4.1.1. Direct-current Generators


d.c. shunt-wound generator without commutating poles (clockwise sense of rotation)


terminal boards (clockwise sense of rotation)


terminal boards (anti-clockwise sense of rotation)


d.c. shunt-wound generator with commutating poles (clockwise sense of rotation)


The commutating poles are clamped inside the generator terminal boards with commutating poles (clockwise sense of rotation)


The commutating poles are clamped inside the generator terminal boards with commutating poles (anti-clockwise sense of rotation)


d.c. compound-wound generator with commutating poles (clockwise sense of rotation)


terminal boards (clockwise sense of rotation)


terminal boards (anti-clockwise sense of rotation)

4.1.2. Direct-current Motors


d.c. shout-wound motor with commutating poles and starter (clockwise sense of rotation)


d.c. shout-wound motor with commutating poles and starter (anti-clockwise sense of rotation)

The commutating poles are clamped inside the motor


terminal boards (A)


terminal boards (B)


d.c. series motor with commutating poles (clockwise sense of rotation)


d.c. series motor with commutating poles (anti-clockwise sense of rotation)


terminal boards (A)


terminal boards (B)


d.c. compound - wound motor with commutating poles (clockwise sense of rotation)


d.c. compound - wound motor with commutating poles (anti-clockwise sense of rotation)


terminal boards (A)


terminal boards (B)


d.c. shunt-wound motor with cylindrical starter (clockwise sense of rotation)


d.c. series motor with cylindrical starter (clockwise sense of rotation)


d.c. series motor with reversing starter


Schematic circuit diagram for reversing starter with d.c. series motor (clockwise sense of rotation)


Schematic circuit diagram for reversing starter with d.c. series motor (anti-clockwise sense of rotation)


d.c. shunt-wound motor with controller drum for clockwise and anti-clockwise sense of rotation


d.c. shunt-wound motor with controller drum for clockwise and anti-clockwise rotation and braking


Schematic circuit diagram for controller drum with reversing and braking circuit for d.c. shunt-wound motor (clockwise sense of rotation)


Schematic circuit diagram for controller drum with reversing and braking circuit for d.c. shunt-wound motor (anti-clockwise sense of rotation)


Schematic circuit diagram for controller drum with reversing and braking circuit for d.c. shunt-wound motor (braking right-hand side)


Schematic circuit diagram for controller drum with reversing and braking circuit for d.c. shunt-wound motor (braking left-hand side)

4.2. Three-phase Machines

4.2.1. Three-phase Generators


Three-phase generator with exciter (A)


Three-phase generator with exciter (B)

4.2.2. Three-phase Motors

Mains voltage designations

3 N 220V/380V 50 Hz


1 N 220V 50 Hz


Three-phase motor with star-delta connection (star connection)


Three-phase motor with star-delta connection (delta connection)


terminal boards (clockwise sense of rotation)


terminal boards (anti-clockwise sense of rotation)


terminal boards (clockwise sense of rotation)


terminal boards (anti-clockwise sense of rotation)


Three-phase motor with drum switch for clockwise and anti-clockwise rotation


Three-phase motor with lever commutator for star-delta starting


Three-phase motor with dram switch for star-delta starting


Three-phase motor (slip ring rotor) with rotor starter in star connection


Three-phase motor (slip ring rotor) with rotor starter in delta connection and controller drum for clockwise and anti-clockwise rotation


Three-phase motor with protective motor switch for undervoltage tripping, thermal tripping and magnetic tripping


Three-phase motor (slip ring rotor) with rotor starter and protective motor switch for manual and magnetic tripping


Three-phase motor with control acknowledging switch and protective motor switch


Three - phase motor in Dahlander pole-changing connection


Three-phase motor in “with Dahlander pole-changing connection”


Three-phase motor in “reverse Dahlander pole-changing connection”


Rotor-fed three-phase shunt-wound commutator motor


Three-phase motor at the single-phase mains (A)


Three-phase motor at the single-phase mains (B)

explanations to the wiring diagram
c1 operating capacitor, c2 starting capacitor

Frequently it is necessary to connect three-phase not ors to single-phase mains. In this connection, the following disadvantages must be taken into account. The rated output (see rating plate) will be reduced to 80 % to 65 %.

The rated torque will be reduced to 30 %.

The output or power can be calculated according to the following equation:

C = capacity of the capacitor in mF
P = power in kW
U = voltage in V
f = frequency

The following approximate values can be assumed when connecting to single-phase alternating current of 220 V:

Power (kW)

Capacity of the Capacitor

0.10

7

1.00

50

2.00

100


Three-phase series commutator motor

1 OFF position
2 starting, operation
3 braking


Single-phase capacitor motor with auxiliary phase


Repulsion motor


Ward-Leonard Control low-loss speed adjustment at the direct-current motor (General wiring diagram)

4.3. Transformers

4.3.1. Single-phase Transformers


normal circuit


economy circuit

4.3.2. Three-phase Transformers

Three-phase transformers in parallel connection


Transformer station with two transformers connected in parallel

Usual groups of connection for transformers

Designation


Indicator Diagram

Circuit Diagram


Identification number

Group of connection

High Voltage

Lower Voltage

High Voltage

Lower Voltage

Transformation

Three-phase power transformers


Dd 0

0

Yy 0


Dz 0


Dy 5

5

Yd 5


Yz 5


Dd 6

6

Yy 6


Dz 6


Dy 11

11

Yd 11


Yz 11

Single-phase power transformers



Explanations for the table

The table shows the commonly used circuits according to the relevant Standard of the International Electrotechnical Commission (I E C). When multiplying the identification number by 30°, the phase shift of the high voltage side with respect to the lower voltage side is obtained.

Dd 6 means:

D = high voltage side delta connection
d = lower voltage side delta connection

The lower voltage is shifted with respect to the high voltage by 6 x 30° = 180°.

Due to these different circuits, different operational behaviour is attained.

The ratio of transformation is calculated as follows:

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
5. Contactor Circuits
5.1. Types of Excitation of the Control
5.2. Possibilities of Representing Contactor Circuits
5.3. Reversing Contactor Circuits
5.4. Arc Extinguishing Circuits
5.5. Three-contactor Star-delta Connection
5.6. Squirrel-cage Induction Motor
5.7. Sliping Rotor
5.8. Interference Suppression
5.9. Light-current Controlled Power Plant with Impulse Relay

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

5. Contactor Circuits

5.1. Types of Excitation of the Control

Self-excitation

Advantage: no-voltage characteristic


Figure

Separate excitation


Figure

The contactor circuits are provided with permanent contact making


Control current locking

Advantage: By means of the control current locking contactor, no-voltage characteristic is attained in separately excited contactor circuits.

5.2. Possibilities of Representing Contactor Circuits


pulse contact making functional diagram


mixed representation - main circuit (single-pole); control circuit (all-pole)


control circuit - shown in the form of a circuit diagram


sequential circuit - functional diagram


Circuit diagram for the control of the sequential circuit


Sequential circuit with rotation monitors and unlocking switches


Circuit diagram for the sequential circuit with rotating monitors and unlocking switches

5.3. Reversing Contactor Circuits


control current - pulse locking


Circuit diagrams for reversing contactor circuits (pulse locking)

To be used for single drives only, circuit is not safe!


Circuit diagrams for reversing contactor circuits (pulse and holding current locking)


reversing contactor circuit - push - button locking


Circuit diagrams for reversing contactor circuits (Push-button locking)


Circuit diagrams for reversing contactor circuits (Push-button locking arranged as rapid change-over circuit; suitable for smaller motors only)


Reversing contactor circuit with star-delta starting main circuit


Circuit diagram for the control of the reversing contactor circuit with star-delta starting

5.4. Arc Extinguishing Circuits


reversing contactor - rapid changing-over


Arc extinguishing circuit for separate excitation


Circuit diagram for the control of the separately escited arc extinguishing circuit

5.5. Three-contactor Star-delta Connection


main circuit


Circuit diagram for the control of the three-contactor star-delta connection

5.6. Squirrel-cage Induction Motor


with effective resistance for starting in the stator and self-monitoring (unsymmetric circuit)


Circuit diagram for the control of the starting action with effective resistance

5.7. Sliping Rotor


with rotor contactor starter


Circuit diagram for the control of the slip-ring rotor with rotor starter

5.8. Interference Suppression


Interference suppression of a universal motor


Interference suppression of a direct-current shunt motor


Interference suppression of switch gears


Interference suppression of electric bells (A)


Interference suppression of electric bells (B)

5.9. Light-current Controlled Power Plant with Impulse Relay


Figure


Figure


Figure

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
6. Rectifier Circuits
6.1. Rectifier Circuits of Alternating Current
6.2. Rectifier Circuits of Three-phase Current

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

6. Rectifier Circuits

6.1. Rectifier Circuits of Alternating Current


half-wave rectification


full wave rectification opposite-contact connection


full-wave rectification - bridge connection


full-wave rectification - thermionic rectifier in double-way connection

6.2. Rectifier Circuits of Three-phase Current


half-wave rectification


full-wave rectification - bridge connection


full-wave rectification - transformer with central tapping

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
7. Measurement Circuits
7.1. Measurement Circuits in Direct-current Installations
7.2. Measurement Circuits in Alternating-current Installations
7.3. Measurement Circuits in Three-phase Installations

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

7. Measurement Circuits

7.1. Measurement Circuits in Direct-current Installations


Voltage measurement (A)


Voltage measurement (B)

By connecting in series of a resistor (Rv), an extension of the measuring range of the voltmeter is obtained


Current measurement (A)


Current measurement (B)

By connecting in parallel a shunt resistor (Rp), an extension of the measuring range of the ammeter is obtained.


Voltage and current measurement for the determination of the resistance

The current-exact connection is used when the resistance (Rx) to be determined, is very high.


Current and voltage measurement for the determination of the resistance

The voltage-exact connection is used when the resistance (Rx) to be determined is very small if the resistance Rx is calculated according to the following equation:

7.2. Measurement Circuits in Alternating-current Installations


Voltage measurement (low voltage)


Voltage measurement (high-voltage - voltmeter with voltage transformer)


Current measurement


Current measurement (amperemeter with current transformer)


Power measurement (low voltage)


Power measurement (high voltage)


electric meter connections


electric meter connections

7.3. Measurement Circuits in Three-phase Installations


Voltage measurement


2 voltage transformers in V-connection


Current measurement


Current measurement


Power measurement

Single wattmeter method

use:

equal phase loading, accessible PEN-conductor

result:

total power = 3 × measuring result


Power measurement

Two-wattmeter method

use:

unequal phase loading, non-accessible PEN-conductor;
measuring instruments of the same type have to be used

result:

total power = P1 + P2,
when P1 > P2, the total power = P1 - P2


Power measurement

Two-wattmeter method
2 movements combined into one instrument


Power measurement

Three-wattmeter method

use: unequal phase loading, accessible PEN-conductor
result: total power = P1 + P2 + P3


Power measurement

Three - wattmeter method
3 movements combined into one instrument


Meter circuit (three-wire meter)


Meter circuit (four-wire meter)


Measurement of the power factor (cos j)


Measurement of the frequency (single frequency meter)


Measurement of the frequency (double frequency meter)


Measurements in a High-voltage Power Plant

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
(introduction...)
Preface
1. Selected Graphical Symbols of Electrotechnology
2. Bell Circuits
3. Basic Circuits of Illumination Engineering
4. Electrical Machines
5. Contactor Circuits
6. Rectifier Circuits
7. Measurement Circuits
8. Protective Circuits
9. Circuits in Motor Vehicles
10. Tables
11. Basic symbols and formulas of electrical engineering

8. Protective Circuits


Protective wire in a three-phase current system


Earthing (Three-phase a-c three wire system)


Earthing (Three-phase a-c four wire system)

Protective Earthing


Reflux of the leakage current via water pipe system (1)


Reflux of the leakage current via earth

IF leakage current, In rated current of the fusible cut-out


Circuit for Generating Protective Low Voltage

Fault-voltage Protective Circuit


in a three-phase three-wire system

1 fault-voltage circuit breaker

Fault-current Protective Circuit


in a three-phase four-wire system

1 fault-current circuit breaker

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
9. Circuits in Motor Vehicles
(introduction...)
9.1. Battery Charge
9.2. Ignition Systems
9.3. Starting Aid for Diesel Engines
9.4. Turn-signal Flasher

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

9. Circuits in Motor Vehicles

Block diagram

The block diagram represents the simplified circuit. Only the essential parts are taken into consideration. The devices are copied by means of rectangles or squares and properly marked.


Figure

Terminal diagram

The terminal diagram represents the electrical connection between the devices. Thus it allows the exchange of products, devices and parts of devices. The components are represented with the corresponding lines, junctions and terminal designations.


Figure

Circuit diagram

The circuit diagram is the detailed representation of a circuit. It represent the operating method of an electrical system or of single devices. The devices are drawn in their basic setting and in dead condition.


Figure

9.1. Battery Charge


General wiring-diagram


Battery charger 6/12 V switchable


Battery charger 6/12 switchable with built-in charge indicator lamp and measuring instrument

9.2. Ignition Systems

Battery-ignition systems


General wiring diagram

Transistorized ignition systems


General wiring diagram


Variants of transistorized ignition systems (A)


Variants of transistorized ignition systems (B)


Transistorized ignition (Bosch)

9.3. Starting Aid for Diesel Engines


Terminal diagram of a preheating system

1 glow-plug and starter switch, 2 glow-plug indicator, 3 ballast resistor, 4 glow plugs


Preheating with automatic re-annealing after starting

1 headlamp-ignition switch, 2 glow-plug and starter switch, 3 contactor, 4 charge indicator lamp (as glow-plug indicator), 5 resistor, 6 time-delay switch, 7 starter

9.4. Turn-signal Flasher


Turn-signal flasher with two turn-signal lamps and indicator lamp


Turn-signal flasher with three turn-signal lamps and turn-signal lamp


Turn-signal flasher with three turn-signal lamps and two turn-signal lamps

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
(introduction...)
Preface
1. Selected Graphical Symbols of Electrotechnology
2. Bell Circuits
3. Basic Circuits of Illumination Engineering
4. Electrical Machines
5. Contactor Circuits
6. Rectifier Circuits
7. Measurement Circuits
8. Protective Circuits
9. Circuits in Motor Vehicles
10. Tables
11. Basic symbols and formulas of electrical engineering

10. Tables

Table 1 Natural values of the trigonometric functions sine and cosine

sin 0°...sin 15°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


0

0,00000

00175

00349

00524

00698

00873

01047

01222

01396

01571

01745

89

1

01745

01920

02094

02269

02443

02618

02792

02967

03141

03316

03490

88

2

03490

03664

03839

04013

04188

04362

04536

04711

04885

05059

05234

87

3

05234

05408

05582

05756

05931

06105

06279

06453

06627

06802

06976

86

4

06976

07150

07324

07498

07672

07846

08020

08194

08368

08542

08716

85

5

08716

08889

09063

09237

09411

09585

09758

09932

10106

10279

10453

84

6

10453

10626

10800

10973

11147

11320

11494

11667

11840

12014

12187

83

7

12187

12360

12533

12706

12880

13053

13226

13399

13572

13744

13917

82

8

13917

14090

14263

14436

14608

14781

14954

15126

15299

15471

15643

81

9

15643

15816

15988

16160

16333

16505

16677

16849

17021

17193

17365

80

10

0,17365

17537

17708

17880

18052

18224

18395

18567

18738

18910

19081

79

11

19081

19252

19423

19595

19766

19937

20108

20279

20450

20620

20791

78

12

20791

20962

21132

21303

21474

21644

21814

21985

22155

22325

22495

77

13

22495

22665

22835

23005

23175

23345

23514

23684

23853

24023

24192

76

14

24192

24362

24531

24700

24869

25038

25207

25376

25545

25713

25882

75


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 75°...cos 90°

Natural values of the trigonometric functions sine and cosine

sin 15°...30°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


15

25882

26050

26219

26387

26556

26724

26892

27060

27228

27396

27564

74

16

27564

27731

27899

28067

28234

28402

28569

28736

28903

29070

29237

73

17

29237

29404

29571

29737

29904

30071

30237

30403

30570

30736

30902

72

18

30902

31068

31233

31399

31565

31730

31896

32061

32227

32392

32557

71

19

32557

32722

32887

33051

33216

33381

33545

33710

33874

34038

34202

70

20

0,34202

34366

34530

34694

34857

35021

35184

35347

35511

35674

35837

69

21

35837

36000

36162

36325

36488

36650

36812

36975

37137

37299

37461

68

22

37461

37622

37784

37946

38107

38268

38430

38591

38752

38912

39073

67

23

39073

39234

39394

39555

39715

39875

40035

40195

40355

40514

40674

66

24

40674

40833

40992

41151

41310

41469

41628

41787

41945

42104

42262

65

25

42262

42420

42578

42736

42894

43051

43209

43366

43523

43680

43837

64

26

43837

43994

44151

44307

44464

44620

44776

44932

45088

45243

45399

63

27

45399

45554

45710

45865

46020

46175

46330

46484

46639

46793

46947

62

28

46947

47101

47255

47409

47562

47716

47860

48022

48175

48328

48481

61

29

48481

48634

48786

48938

49090

49242

49394

49546

49697

49849

50000

60


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 75°...60°

Natural values of the trigonometric functions sine and cosine

sin 30°...45°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


30

0,50000

50151

50303

50453

50603

50754

50904

51054

51204

51354

51504

59

31

51504

51653

51803

51952

52101

52250

52399

52547

52696

52844

52992

58

32

52992

53140

53288

53435

53583

53730

53877

54024

54171

54317

54464

57

33

54464

54610

54756

54902

55048

55194

55339

55484

55630

55775

55919

56

34

55919

56064

56208

56353

56497

56641

56784

56928

57071

57215

57358

55

35

57358

57501

57643

57786

57928

58070

58212

58354

58496

58637

58779

54

36

58779

58920

59061

59201

59342

59482

59622

59763

59902

60042

60182

53

37

60182

60321

60460

60599

60738

60876

61015

61153

61291

61429

61566

52

38

61566

61704

61841

61978

62115

62251

62388

62524

62660

62796

62932

51

39

62932

63068

63203

63338

63473

63608

63742

63877

64011

64145

64279

50

40

0,64279

64412

64546

64679

64812

64945

65077

65210

65342

65474

65606

49

41

65606

65738

65869

66000

66131

66262

66393

66523

66653

66783

66913

48

42

66913

67043

67172

67301

67430

67559

67688

67816

67944

68072

68200

47

43

68200

68327

68455

68582

68709

68835

68962

69088

69214

69340

69466

46

44

69466

69591

69717

69842

69966

70091

70215

70339

70463

70587

70711

45


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 60°...45°

Natural values of the trigonometric functions sine and cosine

sin 45°...60°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


45

0,70711

70834

70957

71080

71203

71325

71447

71569

71691

71813

71934

44

46

71934

72055

72176

72297

72417

72537

72657

72777

72897

73016

73135

43

47

73135

73254

73373

73491

73610

73728

73846

73963

74080

74198

74314

42

48

74314

74431

74548

74664

74780

74896

75011

75126

75241

75356

75471

41

49

75471

75585

75700

75813

75927

76041

76154

76267

76380

76492

76604

40

50

0,76604

76717

76828

76940

77051

77162

77273

77384

77494

77605

77715

39

51

77715

77824

77934

78043

78152

78261

78369

78478

78586

78694

78801

38

52

78801

78908

79016

79122

79229

79335

79441

79547

79653

79758

79864

37

53

79864

79968

80073

80178

80282

80386

80489

80593

80696

80799

80902

36

54

80902

81004

81106

81208

81310

81412

81513

81614

81714

81815

81915

35

55

81915

82015

82115

82214

82314

82413

82511

82610

82708

82806

82904

34

56

82904

83001

83098

83195

83292

83389

83485

83581

83676

83772

83867

33

57

83867

83962

84057

84151

84245

84339

84433

84526

84619

84712

84805

32

58

84805

84897

84989

85081

85173

85264

85355

85446

85536

85627

85717

31

59

85717

85806

85896

85985

86074

86163

86251

86340

86427

86515

86603

30


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 30°...45°

Natural values of the trigonometric functions sine and cosine sin

sin 60°...75°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


60

0,86603

86690

86777

86863

86949

87036

87121

87207

87292

87377

87462

29

61

87462

87546

87631

87715

87798

87882

87965

88048

88130

88213

88295

28

62

88295

88377

88458

88539

88620

88701

88782

88862

88942

89021

89101

27

63

89101

89180

89259

89337

89415

89493

89571

89649

89726

89803

89879

26

64

89879

89956

90032

90108

90183

90250

90334

90408

90483

90557

90631

25

65

90631

90704

90778

90851

90924

90996

91068

91140

91212

91283

91355

24

66

91355

91425

91496

91566

91636

91706

91775

91845

91914

91982

92050

23

67

92050

92119

92186

92254

92321

92388

92455

92521

92587

92653

92718

22

68

92718

92784

92849

92913

92978

93042

93106

93169

93232

93295

93358

21

69

93358

93420

93483

93544

93606

93667

93728

93789

93849

93909

93969

20

70

0,93969

94029

94088

94147

94206

94264

94322

94380

94438

94495

94552

19

71

94552

94609

94665

94721

94777

94832

94888

94943

94997

95052

95106

18

72

95106

95159

95213

95266

95319

95372

95424

95476

95528

95579

95630

17

73

95630

95681

95732

95782

95832

95882

95931

95981

96029

96078

96126

16

74

96126

96174

96222

96269

96316

96363

96410

96456

96502

96547

96593

15


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 15°...30°

Natural values of the trigonometric functions sine and cosine

sin 75°...90°

minute

0

6

12

18

24

30

36

42

48

54

60


degree

,0

,1

,2

,3

,4

,5

,6

,7

,8

,9

(1,0)


75

96593

96638

96682

96727

96771

96815

96858

96902

96945

96987

97030

14

76

97030

97072

97113

97155

97196

97237

97278

97318

97358

97398

97437

13

77

97437

97476

97515

97553

97592

97630

97667

97705

97742

97778

97815

12

78

97815

97851

97887

97922

97958

97992

98027

98061

98096

98129

98163

11

79

98163

98196

98229

98261

98294

98325

98357

98389

98420

98450

98481

10

80

0,98481

98511

98541

98570

98600

98629

98657

98686

98714

98741

98769

9

81

98769

98796

98823

98849

98876

98902

98927

98953

98978

99002

99027

8

82

99027

99051

99075

99098

99122

99144

99167

99189

99211

99233

99255

7

83

99255

99276

99297

99317

99337

99357

99377

99396

99415

99434

99452

6

84

99452

99470

99488

99506

99523

99540

99556

99572

99588

99604

99619

5

85

99619

99635

99649

99664

99678

99692

99705

99731

99731

99744

99756

4

86

99756

99768

99780

99792

99803

99813

99824

99834

99844

99854

99863

3

87

99863

99872

99881

99889

99897

99905

99912

99919

99926

99933

99939

2

88

99939

99945

99951

99956

99961

99966

99979

99974

99978

99982

99985

1

89

99985

99988

99990

99993

99995

99996

99998

99999

99999

1.00000

1.00000

0


(1,0)

,9

,8

,7

,6

,5

,4

,3

,2

,1

,0

degree


60

54

48

42

36

30

24

18

12

6

0

minute

cos 15°...0°

Table 2 Resistances and weights of copper wires

Diameter

Cross section

Resistance per km with 15°(288 k)

Length of a wire of 1 W

Weight per km

Length of a wire of 1 kg

mm

mm2

W

m

kg

m

0,1

0,0079

2215

0,4514

0,070

14306

0,2

0,0314

553,9

1,856

0,280

3577

0,3

0,0707

246,2

4,062

0,629

1590

0,4

0,1257

138,5

7,222

1,118

894,1

0,5

0,1964

88,62

11,28

1,748

572,2

0,6

0,2827

61,54

16,25

2,516

397,4

0,7

0,3848

45,21

22,12

3,425

292,0

0,8

0,5026

34,62

28,89

4,474

223,5

0,9

0,6362

27,35

36,56

5,662

176,6

1,0

0,7854

22,15

45,14

6,990

143,1

1,1

0,9503

18,31

54,62

8,458

118,2

1,2

1,1310

15,38

65,00

10,07

99,35

1,3

1,3273

13,11

76,28

11,81

84,65

1,4

1,5394

11,30

88,47

13,70

72,99

1,5

1,7671

9,846

101,6

15,73

63,58

1,6

2,0106

8,654

115,6

17,89

55,88

1,7

2,2698

7,666

130,5

20,20

49,50

1,8

2,5447

6,838

146,2

22,65

44,15

1,9

2,8353

6,137

162,9

25,23

39,63

2,0

3,1416

5,539

180,6

27,96

35,77

2,1

3,4636

5,024

199,1

30,83

32,44

2,2

3,8013

4,577

218,5

33,83

29,56

2,3

4,1548

4,188

238,8

36,98

27,04

2,4

4,5239

3,846

260,0

40,26

24,84

2,5

4,9087

3,545

282,1

43,69

22,89

2,6

5,3093

3,277

305,1

47,25

21,16

2,7

5,7256

3,039

329,1

50,96

19,62

2,8

6,1575

2,826

353,9

54,80

18,25

2,9

6,6052

2,634

379,6

58,79

17,01

3,0

7,0686

2,462

406,2

62,91

15,90

3,1

7,5477

2,305

433,8

67,17

14,89

3,2

8,0425

2,164

462,2

71,58

13 79

3,3

8,5530

2,034

491,6

76,12

13,14

3,4

9,0792

1,916

521,8

80,80

12,38

3,5

9,6211

1,809

552,9

85,63

11,68

3,6

10,1790

1,709

585,0

90,59

11,04

3,7

10,752

1,618

617,9

95,69

10,45

3,8

11,341

1,534

651,8

100,9

9,907

3,9

11,946

1,457

686,5

106,3

9,406

4,0

12,566

1,385

722,2

111,8

8,941

4,1

13,203

1,318

758,8

117,5

8,510

4,2

13,854

1,256

796,2

123,3

8,110

4,3

14,522

1,198

834,6

129,2

7,737

4,4

15,205

1,144

873,9

135,3

7,389

4,5

15,904

1,094

914,0

141,5

7,065

4,6

16,619

1,047

955,1

147,9

6,761

4,7

17,349

1,003

997,1

154,4

6,476

4,8

18,096

0,9616

1040

161,1

6,209

4,9

18,857

0,9227

1084

167,8

5,958

5,0

19,635

0,8862

1128

174,7

5,722

5,1

20,428

0,8518

1174

181,8

5,500

5,2

21,237

0,8193

1221

189,0

5,291

5,3

22,062

0,7887

1268

196,4

5,093

5,4

22,902

0,7598

1316

203,8

4,906

5,5

23,758

0,7324

1365

211,5

4,729

5,6

24,630

0,7065

1416

219,2

4,562

5,7

25,518

0,6819

1467

227,1

4,403

5,8

26,421

0,6586

1518

235,1

4,253

5,9

27,340

0,6463

1571

243,3

4,110

6,0

28,274

0,6154

1625

251,6

3,974

6,1

29,225

0,5974

1680

260,1

3,845

6,2

30,191

0,5763

1735

268,7

3,722

6,3

31,172

0,5582

1792

277,4

3,604

6,4

32,170

0,5409

1849

286,3

3,493

6,5

33,183

0,5244

1907

295,3

3,386

6,6

34,212

0,5086

1966

304,5

3,284

6,7

35,257

0,4935

2026

313,8

3,187

6,8

36,317

0,4791

2087

323,2

3,094

6,9

37,393

0,4653

2149

332,8

3,005

Table 3 Specific resistance and conductivity of essential materials at 20° C (193 K)

Material

Spec. Resistance

Conductivity


Aluminium, soft

0,028

36

Lead

0,2

5

Gold

0,022

45

Copper E-Cu, soft

0,01754

57

Brass Ms 58

0,059

17

Brass Ms 63

0,071

14

Nickel silver NiMs

0,5...0,15

2,0...6,7

Platinum

0,098

10,2

Mercury

0,960

1,042

Silver

0,01629

61,4

Steel, ingot iron

0,12

8

Grey iron

1

1

Tungsten

0,059

17

Zinc

0,062

16


Resistance alloy:


Chrome nickel

1...1,2

1...0,83

Constantan (WM 50)

0,5

2

Manganin

0,4

2,5

Niccolite

0,5

2

Al-Cr-Steel

1,4

0,7

Arc lamp carbon

13...100

0,08...0,01

Table 4 Temperature coefficient

Material

Temperature coefficient of an electrical resistance between 0° and 100° C (173 and 273 K)

Aluminium

+0,0037

Aluminium bronze

+0,001

Lead

+0,00417

Iron

+0,0045

Electron


Constantan

0,00005

Copper

+0,0043

Manganin

+0,00001

Brass

+0,0015

Molybdenum

+0,0043

Nickel silver

+0,00007

Nickel

+0,0041

Niccolite

+0,00022

Platinum

+0,0039

Platinum-Rhodium (10 % Rh.)

+0,0017

Mercury

+0,00090

Silver

+0,0036

Steel

+0,0045... 0,005

Tantalum

+0,0034

Bismuth

+0,0037

Tungsten

+0,004-1

Zinc

+0,0039

Tin

+0,0042

Table 5 Values of current-carrying capacity and maximum permissible rated current of the overcurrent protection device for lines with copper conductor and plastic, silicone-rubber or glass-silk insulation

Conductor cross-sectional area

Current-carrying capacity

Rated current of overcurrent protection device


A

A

mm2

1

2

3

4

1

2

3

4

0,5

12

10

9

8

10

10

6

6

0,75

16

13

12

11

16

10

10

10

1,0

20

17

15

14

20

16

10

10

1,5

26

22

20

18

25

20

20

16

2,5

36

31

27

24

36

25

25

20

4

50

43

38

34

50

36

36

25

6

63

54

50

46

63

50

50

36

10

86

74

64

59

80

63

63

50

16

117

101

87

80

100

100

80

80

25

155

133

116

105

125

125

100

100

35

192

165

144

130

160

160

125

125

50

240

206

180

163

224

200

160

160

70

300

259

225

204

300

250

224

200

95

365

314

274

248

355

300

250

224

120

425

366

319

289

425

355

300

250

150

480

413

360

326

425

355

355

300

185

542

466

406

368

500

425

355

355

240

640

551

480

435

600

500

425

425

300

735

633

551

500

600

600

500

500

These values also apply to three-phase four-wire systems with neutral conductor and separate protective conductor (five-wire systems).

Pay attention to the current-carrying capacity factors according to the Tables 9 to 12.

Table 6 Values of current-carrying capacity and maximum permissible rated current of the overcurrent protection device for lines with aluminium conductor and plastic, silicone-rubber and glass-silk insulation

Conductor cross- sectional area

Current-carrying capacity

Rated current of overcurrent protection device


A

A


for number of cores carrying current in operation

mm2

1

2

3

4

1

2

3

4

2,5

27

23

30

18

25

20

20

16

4

37

32

28

24

36

25

25

20

6

50

43

37

34

50

36

36

25

10

67

57

50

46

63

50

50

36

16

90

77

67

61

80

63

63

50

25

120

103

90

81

100

100

80

80

35

148

127

111

100

125

125

100

100

50

187

161

140

127

160

160

125

125

70

231

200

173

154

200

200

160

125

95

282

243

212

191

250

224

200

160

120

328

283

246

223



224

200

150

376

325

283

249

355

300

250

224

185

480

370

322

292

425

355

300

250

240

502

492

376

342

500

425

355

300

300

578

497

433

395

500

425

425

355

Use:

With more than one conductor (core), the current-carrying capacity and the rated current of the overcurrent protection device are reduced as stated above.

The values also apply to three-phase four-wire systems with neutral conductor and separate protective conductor (five-wire systems).

Pay attention to the current-carrying capacity factors according to the tables 9 to 12.

Table 7 Values of current-carrying capacity and maximum permissible rated current of the overcurrent protection device for rubber-insulated lines with copper conductor

Conductor cross-sectional area

Current-carrying capacity

Rated current of overcurrent protection device


A

A


for number of cores carrying current in operation

mm2

1

2

3

4

1

2

3

4

0,5

11

9

9

8

10

6

6

6

0,75

15

12

11

10

10

10

10

10

1

19

16

14

13

16

16

10

10

1,5

24

21

19

17

20

20

16

16

2,5

34

29

25

23

25

25

25

20

4

47

41

36

32

36

36

36

25

6

60

51

47

43

50

50

36

36

10

82

70

61

56

80

63

50

50

16

111

96

83

76

100

80

80

63

25

147

126

110

100

125

125

100

100

35

182

157

137

124

160

125

125

100

50

229

196

171

155

224

160

160

125

70

285

246

214

194

250

224

200

160

95

347

300

260

236

300

300

250

224

120

404

348

303

274

355

300

300

250

150

456

393

342

310

425

355

300

300

185

515

442

385

350

500

425

355

300

240

608

523

456

413

600

500

425

355

300

700

602

523

475

600

600

500

425

Use:

With more then one conductor (core), the current-carrying capacity and the rated current of the overcurrent protection device are reduced as stated above.

The values also apply to three-phase four-wire systems with neutral conductor and separate protective conductor (five-wire systems).

Pay attention to the current-carrying capacity factors according to the Tables 9 to 12.

Table 8

Values of current-carrying capacity and maximum permissible rated current of the overcurrent protection device for rubber-insulated lines with aluminium conductor

Conductor cross-sectional area

Current-carrying capacity

Rated current of overcurrent protection device


A

A


for number of cores carrying current in operation

mm2

1

2

3

4

1

2

3

4

2,5

26

22

19

17

25

20

16

16

4

35

30

27

23

25

25

25

20

6

47

41

35

32

36

36

25

25

10

63

54

47

44

63

50

36

36

16

85

73

64

58

80

63

63

50

25

144

98

85

77

100

80

80

63

35

141

121

105

95

125

100

100

80

50

178

153

133

121

160

125

125

100

70

220

190

164

146

200

160

160

125

95

268

231

202

182

250

224

200

160

120

312

269

234

212

300

250

224

200

150

358

309

269

236

355

300

250

224

185

408

351

306

278

355

300

300

250

240

477

410

358

325

425

355

355

300

300

550

472

412

374

500

425

355

355

Use:

With more than one conductor (core), the current-carrying capacity and the rated current of the overcurrent protection device is reduced as sated above.

The values also apply to three-phase four-wire systems with neutral conductor and separate protective conductor (five-wire systems).

Pay attention to the current-carrying capacity factors according to the Tables 9 to 12.

Current-carrying capacity factors

These are factors by which the values of current-carrying capacity given in the Tables 6 to 8 have to be multiplied when special conditions are given.

These conditions may be:

- bundled lines installed freely in air
- bundled lines installed in pipes or conduit subways
- multicore lines with more than 4 conductors (cores)
- multicore lines installed in a piled-up arrangement which are loaded at the same time
- ambient temperatures which deviate from 25° C (298 K) and are higher

If multicore lines are fastened individually by means of spacing clips side by side, the current-carrying capacity factor of 0,9 is applicable irrespective of the number of lines placed side by side.

In the case of ambient temperatures higher than 25° C (298 K), the limiting temperature for the conductor of the line used must be taken into consideration.

There are limiting temperatures of conductors

· of 60°C (333 K),
· of 70°C (343 K) and
· of 180°C (453 K).

If several current-carrying capacity factors are applicable, then the values of current-carrying capacity given in the Tables 6 to 8 must be multiplied by all of the applicable factors.

The rated current of the overcurrent protection device must be specified according to the newly calculated current-carrying capacity when factors of the current-carrying capacity are used.

In this event, the rated current of the overcurrent protection device must be below the value of the newly calculated current-carrying capacity of the line.

Table 9 Current-carrying capacity factors for single-core lines bunched and laid out as open-wire line, in pipe trench or service duct or for multi-core lines with more than 4 cores

Number of lines or cores

Current-carrying capacity factor

2

0,85

3

0,75

4

0,68

5

0,62

6

0,58

7

0,55

8

0,53

9

0,50

10

0,48

15

0,42

20

0,38

25

0,35

30

0,33

35

0,31

40

0,30

45

0,29

50

0,28

Table 10 Current-carrying capacity factors for bunched multi-core lines

Number of multi-core lines

Current-carrying capacity factors in case of


open-air bunching

direct side-by side arrangement on walls or ceilings

bunching in pipe trench or service duct

2

0,89

0,83

0,81

3

0,80

0,76

0,75

4

0,73

0,73

0,69

5

0,69

0,71

0,65

6

0,66

0,70

0,62

7

0,63

0,69

0,60

8

0,61

0,69

0,58

9

0,59

0,68

0,56

10

0,57

0,68

0,55

15

0,50

0,66

0,49

20

0,47

0,64

0,46

25

0,44

0,62

0,43

30

0,42

0,60

0,41

35

0,40

0,59

0,40

40

0,39

0,58

0,39

Table 11 Factors of current-carrying capacity in dependence of constant ambient temperatures for lines with a conductor limiting temperature in continuous operation of 60° C (333 K) and 70° C (343 K)

Ambient temperature

Current-carrying with a conductor capacity factors for lines limiting temperature of

°C

(K)

60°C (333 K)


70°C (343 K)

5

(278)


1,25


10

(283)


1,19


15

(288)


1,13


20

(293)


1,07


25

(298)


1,00


30

(303)

0,92


0,94

35

(308)

0,83


0,87

40

(313)

0,74


0,80

45

(318)

0,63


0,72

50

(323)

0,51


0,64

55

(328)

0,36


0,55

60

(333)

-


0,46

65

(338)

-


0,37

Table 12 Factors of current-carrying capacity in dependence of constant ambient temperatures for lines with a conductor limiting temperature of 180°C

Ambient temperature

Current-carrying capacity factor

Ambient temperature

Current-carrying capacity factor

°C

(K)


°C

(K)


55

(328)

1,00

120

(393)

0,69

60

(333)

0,98

130

(403)

0,63

70

(343)

0,94

140

(413)

0,56

80

(353)

0,90

150

(423)

0,49

90

(363)

0,85

160

(433)

0,40

100

(373)

0,80

170

(443)

0,28

110

(383)

0,75

175

(448)

0,20

Example:

A seven-core plastic-insulated line with copper conductor o and a conductor rated cross-sectional area of 1,5 mm is to be installed at a constant ambient temperature of 35°C (308 K). What is the current-carrying capacity of the line with a conductor limiting temperature of 70°C (343 K)?

Solution:

According to Table 5, the current-carrying capacity of one core is 26 A.

For 7 cores, the factor of current-carrying capacity is 0,55; at a constant ambient temperature of 35°G (308 K) the factor of current-carrying capacity is 0,87 (conductor limiting temperature 70°C or 343 K) according to Table 10.

Actual current-carrying capacity

26 A · 0,55 · 0,87 = 12 A.

Rated current for the overcurrent protection device is 10 A.

Table 13 Limiting temperature for conductors

Type of cable

Conductor limiting temperature


°C

(K)




continuously

at short-circuit

1-kV plastic cable

70

(343)

180

(453)

10-,20-,30-kV plastic cable

70

(343)

200

(473)

1-kV solid-type cable

80

(353)

200

(473)

10-kV solid-type cable

55

(328)

165

(438)

20-kV solid-type cable

55

(328)

145

(418)

30-kV solid-type cable

45

(318)

130

(408)

When selecting cables with respect to their current-carrying capacity, the following factors must be taken into consideration:

- The thermal resistance of the soil; it is dependent on the type of soil and the moisture content of the soil.

- Loaded cables, heating lines and the like installed in close vicinity.

- Heat retention due to air cushions, protective covers, in ducts, pipes or nests of tubes.

Table 14 Current-carrying capacity of 1-kV solid-type cables for individual installation, with reduced solid sheath and fully saturated impregnation

Rated cross-sectional area of conductor

Single -core cables

Two-core cables

Three-core and four-core cables

mm2

Cu

Al

Cu

Al

Cu

Al

1,5

-

-

30

-

25

-

2,5

-

-

35

30

30

25

4

-

-

45

35

40

30

6

-

-

60

45

55

40

10

-

-

85

65

75

60

25

-

-

145

115

125

100

50

285

230

215

175

185

150

70

350

280

260

210

225

180

120

495

395

350

280

315

250

185

630

510

450

360

410

330

240

740

590

525

420

475

380

300

840

675

590

470

545

435

400

1000

800

700

565

645

515

500

1140

910

-

-

-

-

1000

1740

1390

-

-

-

-

Table 15 Current-carrying capacity of three unarmoured single-core solid-type cables with lead sheath, fully impregnated, in three-phase systems, separately lying side by side

Nominal cross-section of the conductor

1 kV


Current - carrying capacity in A

mm2

Cu

Al

50

250

200

70

300

240

120

410

330

185

510

405

240

575

460

300

640

510

400

725

580

500

790

630

1000

950

805

The values of Table 15 are applicable to cables lying side by side in a clearance of about 7 cm, in consideration of the metallic sheath losses in case of cable sheaths short-circuited at both cable ends.

The current-carrying capacity of three unarmoured single-core cables with A1-sheath separately lying side by side amounts to 90 % of the values according to Table 15.

Table 16 Current-carrying capacity of three unarmoured single-core solid-type cables with lead sheath, non-draining, in three-phase systems, separately lying side by side

Nominal cross-section of the conductor

1 kV

mm2

Current-carrying capacity in A


Cu

Al

50

250

200

70

300

240

120

410

330

185

510

405

240

575

460

300

640

510

400

725

580

500

790

630

1000

950

805

The values of Table 16 are applicable to cables lying side by side in a clearance of about 7 cm, in consideration of the metallic sheath losses in case of cable sheaths short-circuited at both cable ends.

The current-carrying capacity of three unarmoured single-core non-draining cables with Al-sheath separately lying side by side amounts to 90 % of the values according to Table 16.

The current-carrying capacity of three touching single-core non-draining cables with Al-sheath arranged in a triangle amounts to 105 % of the values according to Table 16.

Table 17 Current-carrying capacity of 1-kV-plastic cables

Nominal cross-section of the conductor

Single-core cables

Two-core cables

Three- and four-core cables


Current-carrying capacity

in A


mm2

Cu

Al

Cu

Al

Cu

Al

1,5

-

-

25

-

20

-

2,5

-

-

30

25

25

20

4

-

-

40

50

35

25

6

-

-

55

40

45

35

10

-

-

75

55

65

50

25

-

-

120

95

110

90

50

260

210

-

-

165

125

70

315

250

-

-

200

155

120

445

360

-

-

285

220

185

570

455

-

-

370

285

240

665

530

-

-

430

335

300

755

605

-

-

-

-

400

880

720

-

-

-

-

500

990

800

-

-

-

-

The carrying capacity specified in the Tables 14...17 is to be reduced to the following specified percentages in case of deviations from the mentioned conditions of installation.

Table 18 Reduction in case of bunched multi-core cables in three-phase systems and cables in direct current systems

Number of cables in the trench


2

3

4

5

6

8

10

Carrying capacity in

%

90

80

75

70

65

62

60

The carrying capacity of cables under protective hoods diminishes to 90 % of the values found out in application of other reductions (see Tables 18...25).

The reductions are applicable to cables lying side by side in a clearance of about 7 cm.

Table 19 Reduction in case of bunched single-core cables in three-phase systems

Number of systems in the trench

2

3

4

Carrying capacity in %

80

75

70

The reductions are applicable to single-core cables lying side by side in a clearance of about 7 cm.

The values of the Tables 20 and 21 are applicable to cables in unarmoured cement pipes in the earth with a clear interior diameter of about 150 mm and 20 mm wall thickness in an horizontal arrangement with reciprocal touch and an outer diameter of 50 mm.

Table 20 Reduction in case of multi-core cables and single-wire cables in single pipes bunched in a triangle

Number of pipes

1

2

3

4

5

6

7

8

9

10

Carrying capacity of the cables in %

80

72

68

65

63

61

60

59

58

57

Table 21 Reduction, in case of single-core cables in single pipes in three-phase systems

Number of pipes

3

6

9

Number of systems

1

2

3

Carrying capacity of the cables in %

85

76

72

Table 22 Reduction in case of bunched cables in the open air

Cable distance

Carrying capacity in %


3 cables or 3 cable systems

6 cables or 6 cables systems

Space between the cables is equal to the cable diameter

93

87

No space between the cables (reciprocal touch)

81

74

Table 23 Reduction in case of an ambient temperature for plastic cables deviating from 20°C

Rated voltage

Carrying capacity in % in case of an ambient temperature of °C

kV

5

10

15

20

25

30

35

40

1

115

110

105

100

95

89

84

77

Example of calculation:

For the transmission of 1,25 MVA with an operating voltage of 6 kV three-phase current a cable is required. This cable is to be hung by means of an auxiliary cable side by side with two cables hanging already in a shaft. The space between the cables is equal to the cable diameter. The ambient temperature is 30°C.

Solution:

A three-core cable with screened cores and with non-draining, intensified insulation is to be chosen.

Table 24 Reduction in case of an ambient temperature for solid-type cables deviating; from 20 %

Rated voltage kV

Carrying capacity in % in case of an ambient temperature of °C


5

10

15

20

25

30

35

40

1

112

108

104

100

96

91

87

82

10,20

120

113

107

100

93

85

76

65

30

126

118

110

100

90

78

63

45

Occuring factors of reduction:

- 93 % for laying three cables side by side (space between the cables = cable diameter, see Table 22).

- 85 % for raised ambient temperature of 30 % (see Table 23).

Total reduction factor = 0,93 · 0,85 » 0,79

Table 25 Continuous carrying capacity of the most important overhead-line materials for an over temperature of 40°C

Cable cross section

Copper

Pure aluminium

Aldrey

Steel-aluminium





1:6

1:4

mm2

A

A

A

A

A

16

115

92

88

-

-

25

151

121

115

-

-

35

174

149

142

145

225

501)

234

187

178

170

300

502)

231

185

176

-

-

70

282

226

215

235

355

95

357

283

269

290

440

120

411

329

313

345

505

150

477

382

363

400

560

185

544

435

414

455

650

2403)

630

502

479

-

-

2404)

641

513

488

530

770

300

747

598

568

615

-

1) 7-wire (1 layer)
2) 19-wire (2 layers)
3) 37-wire (3 layers)
4) 61-wire (4 layers)

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)
11. Basic symbols and formulas of electrical engineering
(introduction...)
11.1. General direct current engineering
11.2. Magnetic field
11.3. Law of induction
11.4. Electric field
11.5. Alternating current engineering
11.6. Calculation of power

Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut f�r Berufliche Entwicklung, 201 p.)

11. Basic symbols and formulas of electrical engineering

The following is valid:

I

= current intensity in A

E

= empressed voltage in V

U

= voltage, terminal voltage in V

R

= resistance in w

L

= inductivity in H

w

= gyro-frequency in or Hz

f

= frequency in or Hz

C

= capacity in F

r

= resistivity in

c

= unit conductance in

A

= conductor cross-section in mm2

d

= diameter in mm

P

= power in W (active power)

Q

= reactive power in Var

S

= apparent power in VA

W

= work in Wh or Ws

cos j

= power factor

h

= efficiency

= flux in A

B

= magnetic induction in T or or

H

= magnetic field strength in

E

= electric field strength in

f

= magnetic flux in Wb or Vs

F

= force in N

v

= velocity in

w

= number of turns

t

= time in s or h

J K

= initial temperature

J W

= final temperature

RK

= resistance at initial temperature

RW

= resistance at final temperature

µ

= temperature coefficient in

p

= 3,14

influence of the temperature on the resistance of the conductor

11.1. General direct current engineering

Ohm’s Law

power

P = U2 · I

[W]


P = I2 · R

[W]


[W]

work

W = U · I · t

[V · A · s = Ws]


W = P · t

[W · s = Ws]

diameter of a conductor

[mm2]

resistance of a conductor

[W]


[W]

influence of temperature on the resistance of the conductor

RW = RK

[1 + µ(J2 - J1)]

Connection of resistances and power sources

· series connection


Figure


Figure

RG = R1 + R2 + R3 (total resistance)

U = U1 + U2 + U3.....

EG = E1 + E2 + E3

condition: Ri1 = Ri2 = Ri3

U = I · Ra

2. Kirchhoff’s Law

The sum of all voltages around a closed path in an electrical system is zero.

The sum of the impressed voltage is equal to the sum of the voltage drops.

· parallel connection


Figure


Figure

RE = equivalent resistance


IG = total current intensity


Condition:


Equal power sources are connected in parallel.


E = E1 = E2 = E3

for 2 resistances connected

for n equal resistances


IG = I1 + I2 + I3

1. Kirchhoff’s Law

At each junction the sum of the currents flowing toward the junction is equal to the sum of the currents flowing away from the junction.

IG - I1 - I2 - I3 = 0


Figure

11.2. Magnetic field

flux:

magnetic flux:

magnetic resistance:

1 = magnetically effective length in m

A = flux passage area in m2

comparative figure ur for air = 1, 000 000 4

magnetic permeability

relative permeability

mr - comparative figure

induction constant

magnetic field strength

magnetic induction

B = m · H = mo · mr · H


11.3. Law of induction

induced voltage

[V]

self-induction




- self-inductance

[H]



[H]


- voltage of the self-induction

[V]

11.4. Electric field

electric field strength


= voltage in V




= thickness of the dielectric in m



charge

Q = I · t

[As]

capacity

[F]


Q = quantity of electricity in AS




C in F (1F = 1 AS/V)



equation of dimensioning


dielectric constant


relative dielectric constant

er: matter constant, relative to the vacuum


absolute dielectric constant


dielectric flux density

D = e · E


11.5. Alternating current engineering

frequency


T = cycle duration in s


gyro-frequency

phase angle

instantaneous value of a sinusoidal a.c. voltage

instantaneous value of a sinusoidal a.c. current

maximum value



- of a sine-wave voltage


U = virtual value



- of a sine current


I = virtual value



inductive resistance

(inductive reactance)

L in H

capacitive resistance

(capacitive reactance)

C = capacity in F


Series connection

impedance

[W]

ohmic drop in voltage

UR = I · R

[V]

inductive voltage drop

UL = I · XL = I · w L

[V]

capacitive voltage drop

[V]

Ohm’s law for alternating current

[A]

Powers in case of single-phase alternating current

apparent power

S = U · I

[VA]

active power

P = U · I · cos z

[W]

reactive power

Q = U · I · sin z

[Var]

power factor


Powers in case of three-phase alternating current

apparent power

[VA]

active power

[W]

reactive power

[Var]

power factor


efficiency for motors and generators



Pe = effective power




Pi = indicated power



speed calculation of three-phase motors rotating field speed


p = number of pole pairs


slip

[%]


n = rotor speed


11.6. Calculation of power

calculation of power losses

PV = power loss in per cent

direct current

[%]

single-phase alternating current

[%]

three-phase alternating current

[%]



[V];

[V]

[V];

[V]

[V];

[V]

Determination of a conductor cross-section

- Calculation of the rated current from current, voltage and power factor.

- Division by all suitable current-carrying capacity factors of the Tables 9 to 12.

- Determination of the conductor cross-section according to the given current-carrying capacity factors after the calculated fictive current.

- Calculation of the conductor cross-sections according to the given power and voltage loss.

- Comparison of the cross-sections found out under the third and fourth point. The greatest is chosen as the cross-section to be installed.

Conversion of the measuring units of work and power

Work

J

erg

kpm

kWh

PSh

kcal

1 1

107

0.102

0.278 · 10-6

0.378 · 10-6

0.239 · 10-3

107

1

0.102 · 10-7

0.278 · 10-13

0.378 · 10-13

0.239 · 10-10

9.81

9.81 · 107

1

2.72 · 10-6

3.70 · 10-6

2.34 · 10-3

3.60 · 106

3.60 · 1013

3.67 · 105

1

1.36

860

2.65 · 106

2.65 · 1013

2.70 · 105

0.7355

1

632

4187

4.19 · 1010

427

1.16 · 10-3

1.58 · 10-3

1

Power

W

kW

kpm s-1

PS

kcal s-1

kcal h-1

1

10-3

0.102

1.36 · 10-3

2.39 · 10-4

0.86

103

1

102

1.36

0.239

860

9.81

9.81 · 10-3

1

0.0133

2.34 · 10-3

8.43

735.5

0.7355

75

1

0.1757

632

4187

4.19

427

5.69

1

3600

1.16

1.16 · 10-3

0.119

1.58 · 10-3

2.78 · 10-4

1

↑ Back to top