ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-3-445-2
NAVY NAVFAC P-8-624-34
(a) Start and operate the generator set and allow it to stabilize at rated load, rated voltage and rated
frequency (speed). During this period, readings of all instruments including thermal instrumentation
shall be recorded at minimum intervals of 10 minutes. If necessary, adjustments to the load, voltage
and rated frequency. However, 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 generator sets utilizing a droop-type speed control system as the prime speed control,
the speed and droop portions of the control maybe adjusted. No other adjustments to the voltage
and frequency control systems shall be made. Adjustments to the load, voltage or frequency
controls shall be recorded on both the data sheet, and recording chart(s). Stabilization will be
considered to have occurred when four consecutive voltage and current recordings of the 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 load, voltage or
frequency has been made.
(b) Perform this test using resistive load only. Remove reactive load after stabilization.
(c) For Class II Sets:
Alternately increase the load, voltage and frequency in small increments until the fuel system
controls are in the maximum fuel position as permitted by the governor control linkage and the
voltage and frequency are within 1 percent of their rated values.
Small increments should be taken to avoid passing the maximum power at the rated
voltage and frequency point and to avoid racing or bogging the engine.
Hold the conditions in step (1) above for two minutes. However, if the voltage and frequency
cannot be maintained within 1 percent of their rated values, the load must be adjusted to the
point at which the voltage and frequency can be maintained within 1 percent of the rated value
for two minutes.
It may be necessary to reduce the load to a value below the rated kilowatt load for a
short period of time to prevent serious overheating or damage to the generator set if
the conditions can not be readily attained. (Monitor instrumentation.) Failure to
observe this caution could result in equipment damage.
At the end of the two minute interval record all instrument readings including thermal
Reduce the load to approximately rated kilowatt load and allow the generator set to cool for
approximately 5 to 10 minutes.
Repeat steps (1) through (4) above until three valid sets of maximum power data are obtained.
(d) For Class I Sets:
Repeat step (c) above but do not adjust the frequency.
Repeat steps (a) through (c) above as applicable for all other voltage connections and