R

crossing of conductor symbols no electrical connection junction of conductors general contact, in particular one that is not readily separable e.g. soldered joint readily separable contact e.g. terminal on controller base terminals:

u nn

1

2

3

1 1 1 1 1 1

1

2 ¥

3 \2

- on connection diagram control panel terminals:

- on connection diagram

line showing the number of circuits e.g. 2 circuits

Combining wires for the sake of simplicity in wiring diagrams

plug or plug pin socket outlet fuse general

Table 27.3 (continued)

Symbols for electrical schematics fuse showing supply side voltage fuse general over voltage discharge device surge arrestor isolating point with plug-in connection earth, general safety conductor, safety earth chassis, general

GND (ground, common chassis)

resistor, general inductor, inductive reactance capacitor, capacitive reactance polarized (electrolytic) capacitor motor, general

-(^J^)- transformer with two separate windings as above (alternative representation)

battery of cells or accumulators (the long line represents the positive pole)

mechanical coupling:

- general symbol

- symbol used when space is limited linear motion:

- to the right

- both directions rotational motion:

- clockwise

Symbols for electrical schematics

-*---- both directions thermostat, hygrostat etc. -------^ e.g. p ^ pressure switch

| - this symbol is used when space is limited

actuator general, e.g. for relay, contactor electromechanical actuator, e.g. showing active winding electromechanical actuator with two windings active in the same direction signal lamp general 'operation'

signal lamp, flashing for fault signal lamp 'fault', emergency lamp buzzer bell horn transducer, signal transducer, transmitter, general symbol

248 Manual of Engineering Drawing Table 27.3 (continued)

Symbols for electrical schematics rectifier, rectifying device general anplifier general symbol oscillograph, general symbol recording measuring device, recorder

Symbols for electrical schematics Variability inherent linear variability under influence of a physical variable inherent non-linear variability under influence of a physical variable continuous variability by mechanical adjustment, general adjustable in steps

recording measuring device, printer remote operation, general adjuster communication (electronic) clock, general non-inherent non-linear variability f / continuous variability by mechanical adjustment, linear continuous variability by mechanical adjustment, non-linear pre-set mechanical adjustment, general symbol tx synchronous clock time clock

—semi-conductor rectifier diode

E ft" C PNP-transistor E - emitter

E C NPN-transistor the collector is connected to the housing

Example:

temperature dependent resistor with negative temperature coefficient (thermistor) Wire colour abbreviations:

time clock

dividing line (e.g. between two zones or to

bl

blue

ws

white

separate a space)

dbl

dark blue

sw

black

i

hbl

light blue

og

orange

example: control panel

rt

red

vl

violet

gb

yellow

gb/gn

yellow/green

gn

green

bn

brown

gr

grey

optocoupler (SCS) combined symbol

International colour code

Colour reference for resistance value and its tolerance

Tolerance class: without colour reference ±

- brown ± As alternative colours the following are valid on the 4th ring: green instead of gold for ± 5% white instead of silver for ± 10%

black

0

0

- *

brown

1

1

0 *

red

2

2

00

orange

3

3

000

yellow

4

4

0 000 *

green

5

5

00 000

blue

6

6

000 000

violet

7

7

0 000 000

grey

8

8

00 000 000

white

9

9

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