To avoid Injury to personnel, no electrical component shall be worked on while energized.
When Is necessary to work In the vicinity of energized equipment, all safety precautions shall
be followed, such as use of rubber blankets for Insulation, use of rubber gloves, and use of
Insulating tools and equipment. All Insulating tools such as rubber gloves and blankets shall
be tested regularly. Disconnect all power before servicing. Residual voltage Is present at the
generator leads even with the regulator turned off. Residual voltages can reach several
hundred volts on this generator. Proper Insulation and Isolation of metering equipment shall
be observed when testing the generator.
Preparation for test.
Connect the load and field instrumentation in accordance with Figure 12-5, for one voltage and
frequency. Connect the signal input of the recording meter(s) to the convenience receptacle of the
set or to the generator coil which is used as the voltage sensing input to the voltage regulator.
(Power the recording meter(s) from the commercial utility.)
Set the recording meter chart speed(s) to a minimum of 6 inches (152.4 mm) per hour. The
following items shall be recorded on both the data sheets and recording chart(s): 1 The date a The
serial number(s) of the recording meter(s) a Generator set identification 4 The recording chart
speed(s) 5 The data reading number.
Place all instrumentation referred to in step b, above, in operation.
Start and operate the generator set and allow the set to stabilize at rated bad, rated voltage, and rated
frequency. During this period, operate the recording meter(s) at a chart speed of not less than 6 inches
(152.4 mm) per hour, and record all instrument readings, including thermal instrumentation, at minimum
intervals of 10 minutes. If necessary, adjustments to the load, voltage, and frequency may be made to
maintain the rated load at the rated voltage and frequency. Adjustments to the voltage and frequency shall
be limited to those adjustments available to the operator: specifically, adjustments to the voltage or
frequency adjust devices. On set utilizing a droop-type speed control system as the prime speed control,
the speed and droop portions of the control may be adjusted. No other adjustments to the voltage and
frequency control systems shall be made. Adjustments to load, voltage, or frequency controls shall be
recorded on both the data sheet and the recording chart(s) at the time of an adjustment. Stabilization shall
be considered to have occurred when four consecutive voltage and current recorded readings of the
generator (or exciter) field either remain unchanged, or have only minor variations about an equilibrium
condition with no evident continued increase or decrease in value after the last adjustment to the bad,
voltage, or frequency has been made.
After stabilization has occurred, drop the bad to no bad, and reapply the rated load in 50 percent load
increments three times to ensure that the no load and rated load voltage and frequency are repeatable and
that the frequency and voltage regulation is within the limits specified in step d(7), below. If any
adjustments are necessary, step (a), above, must be repeated. Reapply the rated load.
The recording meter chart speed(s) shall be 12 inches (305 mm) per minute throughout the remainder of
this test. a each of the following load conditions, operate the set for a minimum of 40 seconds. During
each load condition read and record all instrument readings except thermal instrumentation (for three-
phase sets it is not necessary to record line-to-line voltages). Each load condition shall be applied to the
generator set in one step at the end of the short-term stability period for the previous load condition. The
load conditions are: