PCD235A101 3BHE032025R0101 ABB Central controller (available from stock)

PCD235A101 3BHE032025R0101 ABB Central controller (available from stock)

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contact number:13313705507

contacts：HE

The trip-circuit supervision is based on a constant current injection principle: by

applying operating voltage for the circuit breaker, a constant current is forced to

flow through the external trip circuit. If the resistance of the trip circuit exceeds a

certain limit, due to oxidation or a bad contact, for instance, the trip-circuit

supervision is activated and a warning appears on the LCD together with a fault

code. The warning signal from the trip-circuit supervision can also be routed to SO2

by setting switch SGF1/8 to 1.

Under normal operating conditions, the applied external voltage is divided between

the relay’s internal circuit and the external trip circuit so that at least 20 V remains

over the relay’s internal circuit. If the external trip circuit’s resistance is too high or

the internal circuit’s too low, due to welded relay contacts, for instance, the voltage

over the relay’s internal circuit falls below 20 V (15...20 V), which activates the tripcircuit supervision.

The operation condition is:

U - R +R +R I 20 V AC/DC c ext int s tc ( )× ≥ (5)

Uc = operating voltage over the supervised trip circuit

Ic = current flowing through the trip circuit, ~1.5 mA

Rext = external shunt resistor

Rint = internal shunt resistor, 1 kΩ

Rs = trip coil resistance

The external shunt resistor is used to enable trip-circuit supervision also when the

circuit breaker is open.

The resistance of the external shunt resistor is to be calculated so that it does not

cause malfunction of the trip-circuit supervision or affect the operation of the trip

coil. Too high resistance causes too high voltage drop, which in turn results in the

operation conditions not being fulfilled, whereas too low resistance may cause

faulty operation of the trip coil.

The following values are recommended for the external resistor, Rext: