3-2 SCP 250 Functional Description 911000099Y Rev T
VOLTAGE LIMITING
The SCP 250 voltage limiter prevents the voltage regulator from supplying full or no excitation if utility
power is lost and the generator main breaker remains closed. Voltage limiting is adjustable between
±10% and ±30%.
CONTROL RELAY
The control relay (K1) enables and disables the SCP 250 output and is controlled by the Enable Contact
input (terminals J and K). The Enable Contact input is typically interconnected with external breaker
auxiliary contacts (52b).
When the external breaker is open (52b contacts closed), K1 energizes and its contacts short-circuit the
SCP 250 output terminals together. This disables the SCP 250 output and gives the voltage regulator
total control of generator excitation.
When the external breaker is closed (52b contacts open), K1 de-energizes and enables the SCP 250
output. The SCP 250 control output is applied to the voltage regulator and the SCP 250 assumes a major
portion of excitation control.
To Next Page
Loading...
