f.
Current Balance on Stator Winding Test, by measuring the current
on each phase of the winding with the generator operating at 100 %
of Rated Output Capacity, with the load impedance equal for each
of the three phases: to the performance criteria specified in
paragraph GENERATOR.
g.
Voltage Waveform Deviation and Distortion Test per IEEE Std 115 to
the performance criteria specified in paragraph GENERATOR.
High-speed recording instruments capable of recording voltage
distortion shall be used. Representation of results shall include
appropriate scales to provide a means to measure and interpret
results.
h.
Voltage and Frequency Droop Test. Verify that the output voltage
and frequency are within the specified parameters as follows:
(1.) With the generator operating at no load, adjust voltage and
frequency to rated voltage and frequency. Record the generator
output frequency and line-line and line-neutral voltages.
(2.) Increase load to Rated Output Capacity. Record the
generator output frequency and line-line and line-neutral voltages.
3. Calculate the percent droop for voltage and frequency with the
following equations:
(No-Load Volts) - (Rated Capacity volts)
Voltage droop % = -------------------------------------------- x 100
(Service-Load Volts)
(No-Load Hertz) - (Rated Capacity hertz)
Frequency droop % = ------------------------------------------ x 100
(Service-Load hertz)
4. Repeat steps 1 through 3 two additional times without making
any adjustments.
i.
Frequency and Voltage Stability and Transient Response. Verify
that the engine-generator set responds to addition and dropping of
blocks of load in accordance with the transient response
requirements. Document maximum voltage and frequency variation
from bandwidth and verify that voltage and frequency return to and
stabilize within the specified bandwidth, within the specified
response time period. Document results in tabular form and with
high resolution, high speed strip chart recorders or comparable
digital recorders, as approved by the Contracting Officer.
Tabular data shall include the following:
Ambient temperature (at 15 minute intervals).
Generator output current (before and after load changes).
Generator output voltage (before and after load changes).
Frequency (before and after load changes).
Generator output power (before and after load changes).
SECTION 16263A
Page 70
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