3.14 Circuit breakers
There are two power switches controlled by the controller:
 The generator circuit breaker or contactor – GCB
 The Mains circuit breaker or contactor – MCB (SPtM application only)
It is possible to use either a motorized circuit breaker or contactor. Below is a list of available control
outputs that should fit all types of contactors or breakers. The following rules must be kept to when
designing the wiring of power switches:
ï‚· The control outputs must be configured and wiring of the power switches must be provided in
such a way, that the controller has full control over the breakers – i.e. the controller can open
and close the breaker at any time.
ï‚· The breaker must respond within max. 2 seconds to a close and open command. Special
attention should be paid to opening of motorized circuit breakers, as it could take more than 2
seconds on some types. In such cases it is necessary to use an undervoltage coil for fast
opening.
ï‚· The breaker feedback functions must be configured onto some binary inputs and the signals
from the breakers must be connected to it and provide reliable information about the breaker
position.
3.14.1 Breaker control outputs
An output for control of a contactor. Its state represents the breaker position
requested by the controller. The breaker must react within 2 seconds to a close or
open command, otherwise an alarm is issued.
An output giving a 2 second pulse in the moment the breaker has to be closed. The
output is intended for control of close coils of circuit breakers.
An output giving a pulse in the moment the breaker has to be opened. The pulse
lasts until the feedback deactivates, but at least for 2 seconds. The output is
intended for control of open coils of circuit breakers.
The output is active the whole time the gen-set is running (GCB, not in idle or
cooling) or the controller is switched on (MCB). The output is deactivated for at
least 2 seconds in the moment the breaker has to be switched off. The output is
intended for control of undervoltage coils of circuit breakers.