Adjusts the generator voltage during synchronization to match the bus voltage.
Governor Speed Switch (GS)
Adjusts the generator frequency to maintain 60 hertz at all times.
Adjust the generator frequency during synchronization to bring the generator in synchronization with
Idle/Run Switch (IRS)
In the Idle position the engine will run at a low speed for warm up or maintenance checking. The
generator breaker cannot be closed in this position.
In the Run position the engine will run at full speed for accepting the load. The switch should always
be left in the Run position.
The synchroscope is used for checking synchronization between any generator and the main bus.
When the rotating needle is pointing straight up the generator is synchronized to the bus. When the
rotating needle is pointing straight down the generator is completely (180 electrical degrees) out of
phase with the bus. When the generator is rotating faster than the bus frequency the needle will
rotate counter clock wise. When the generator is rotating slower than the bus frequency the needle
will rotate clock wise.
Generator Selector Switch (GSS)
This switch selects which generator is being synchronized to the main bus.
The off position will turn off the synchroscope but not the voltmeter and frequency meter.
The switch should always be placed in the off position while not being used for synchronization. If the
switch is placed in the position of a generator that is not running the bus voltage will back feed through
the synchroscope to the generator and present hazardous voltages at the generator during
Ground Detector Lights and Test Switch
The lights will be full bright during normal operation when the main bus is energized.
When the test push button is pressed all lamps will maintain the same brightness unless a phase is
grounded or has a resistance to ground. If the phase is grounded the light will go out when the button
is pressed. If the phase has a resistance to ground the lamp will glow dimly in proportion to the
amount of resistance. The grounded wire must be corrected to prevent ground current flowing in the
Potential Transformers (P.T.)
All are rated 50 VA capacity.