4
Installation Checks and Initial Functional Tests
Figure 1: Control Power Disconnects in Switchgear.
Figure 2: Front Panel of GMI Circuit Breaker
Introduction
This section provides a description of the inspections,
checks and tests to be performed on the circuit breaker
prior to operation in the metal-clad switchgear.
Inspections, Checks and Tests without Control Power
Vacuum circuit breakers are normally shipped with their
primary contacts open and their springs discharged.
However, it is critical to first verify the discharged condi-
tion of the spring-loaded mechanisms after de-energizing
control power.
De-Energizing Control Power in Switchgear - When the
circuit breaker is mounted in switchgear, open the control
power disconnect device in the metal-clad switchgear
cubicle. Figure 1 shows the location of the disconnect in a
standard GM switchgear assembly.
The control power disconnect device is located on the
device panel above the lower circuit breaker and below the
upper circuit breaker. Figure 1 shows a pullout type fuse
holder. Removal of the fuse holder de-energizes control
power to the circuit breaker in the respective switchgear
cell. In some switchgear assemblies, a molded case circuit
breaker is used in lieu of the pullout type fuse holder.
Opening this circuit breaker accomplishes the same result:
control power is disconnected.
Spring Discharge Check (Figure 2) - Perform the Spring
Discharge Check before removing the circuit breaker from
the pallet or removing it from the switchgear.
The spring discharge check consists of simply performing
the following tasks in the order given. This check assures
that both the tripping and closing springs are fully
discharged.
1. Press red Trip pushbutton.
2. Press black Close pushbutton.
3. Again press red Trip pushbutton.
4. Verify Spring Condition Indicator shows DISCHARGED.
5. Verify Main Contact Status Indicator shows OPEN.
DANGER
Hazardous voltages and high-speed
mechanical parts.
Will cause death, serious injury, or
property damage.
Read instruction manuals, observe safety
instructions and use qualified personnel.
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