Alpha Technologies CFR Redundant Control Unit - Manual (Page 4)

1.2 A Tour of the RCU
1 Introduction
1.2.1 Front Panel (Figure 1.2)
Input 1 LED:
Shows the presence of AC power at Input 1.
Input 2 LED:
Shows the presence of AC power at Input 2.
Contactor 1 LED:
Shows Contactor 1 is closed, providing primary power to the output.
Contactor 2 LED:
Shows Contactor 2 is closed, providing secondary power to the output.
Output LED:
Shows there is power at the output.
Manual Transfer LED:
Shows both primary and secondary power sources are in phase and that a manual transfer
can be done with the make–before–break manual bypass switch.
Red Alert LED:
Shows that one of the contactors or the control logic has failed.
Input 1 Circuit Breaker:
Provides circuit breaker protection to the primary input and acts as an ON/OFF switch.
Input 2 Circuit Breaker:
Provides circuit breaker protection to the secondary input and acts as an ON/OFF switch.
Select 1 Switch:
Opens the secondary contactor before closing the primary to provide Input 1 power to the
output.
Select 2 Switch:
Opens the primary contactor before closing the secondary to provide Input 2 power to the
output.
Purpose: Describes the RCU’s controls, displays and terminal blocks
(Figures 1.2, 1.3, 1.4, 1.5).
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