ABB CM Folleto de instrucciones - Página 4

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41-181.2K

The contacts are single-pole, double throw. The

moving contact is fastened directly to the disc shaft

and the electrical connection is made thru a spiral

spring fastened to the moving contact arm and frame

assembly.

2.2. INDICATING CONTACTOR SWITCH (ICS)

The dc indicating contactor switch is a small clapper

type device. A magnetic armature, to which leaf-

spring mounted contacts are attached, is attracted to

the magnetic core upon energizing of the switch.

When the switch closes, the moving contacts bridge

two stationary contacts, completing the trip circuit.

Also during this operation two fingers on the arma-

ture deflect a spring located on the front of the

switch, allowing the operation indicator target to

drop.

The front spring, in addition to holding the target, pro-

vides restraint for the armature and thus controls the

pickup value of the switch.

2.3. AC INDICATING CONTACTOR SWITCH

(ASC)

The ac indicating contactor switch unit is a small ac

operated clapper type device. A magnetic armature,

to which leaf-spring mounted contacts are attached,

is attracted to the magnetic core upon energization of

the switch. When the switch closes, the moving con-

tacts bridge two stationary contacts completing the

trip circuit. Also, during the operation, two fingers on

the armature deflect a spring located on the front of

the switch which allows the operation indicator target

to drop.

3.0 CHARACTERISTICS

The non-tapped type CM relay has a minimum

pickup current of one ampere and a continuous ther-

mal rating of seven amperes. The tapped CM relay

has a minimum pickup of 1, 2 or 3 amperes, depend-

ing on the tap setting and a continuous of 7 amperes.

The minimum pickup current is defined as the pickup

current of each electromagnet with the other paired

electromagnet de-energized.

The relay may be utilized for continuous load cur-

rents of from one to seven amperes. The characteris-

tic curve of the relay is shown in figure 3.

Figure 3. Typical Operating Curve of the Type CM Relay

3.1. TRIP CIRCUIT

The main contacts will safely close 30 amperes at

250 volts dc and the seal-in contacts of the indicating

contactor switch will safely carry this current long

enough to trip a circuit breaker.

The indicating contactor switch (ICS) has two taps

that provide a pickup setting on 0.2 or 2 amperes. To

change taps requires connecting the lead located in

front of the tap block to the desired setting by means

of a screw connection.

For 0.5 ampere ACS, the 1 second coil rating is 18.0

amperes ac. For 1.0 ampere ACS, the 1 second coil

rating is 44.0 amperes ac.

3.2. TRIP CIRCUIT CONSTANTS

Contactor Switch –

ICS

0.2 ampere tap - 6.5 ohms dc resistance

2.0 ampere tap - 0.15 ohms dc resistance

ACS

0.5 ampere ACS - 18 ohms ac impedance

1.0 ampere ACS - 4.5 ohms ac impedance

4.0 ENERGY REQUIREMENTS

The burden of each electromagnet is as follows:

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