for illustration of overshoot and
Divide the result obtained in (a) by
rated voltage (as given on the
generator nameplate), then multiply
by 100 to convert to percentage.
Do not use the constant operating
voltage at each load as the divisor
in the computation. Use only the
rated voltage of the generator.
To determine the time required to restore
stable voltage conditions after each load
change (recovery time):
The prescribed steady-state voltage
bandwidth, extended to the point at
which the voltage trace leaves the
prescribed steadystate band, shall
be considered as the time at which
the transient conditions begin. The
point at which the voltage trace
prescribed band after a load change
shall be considered as the point at
which stabilization begins.
Measure the distance (in inches) on
the chart from the point where the
voltage trace leaves the prescribed
steady-state band to the point where
it re-enters and remains within the
prescribed voltage band for the next
Divide this distance by the chart
speed (in inches per second). This
will give the voltage recovery time,
Determine the voltage regulation for all
load changes (for example, rated load to
no load, 1/2 rated load to no load to 1/4
load, etc.) as follows:
readings subtract the load value of
voltage from the no load value for
each load change (for example step
(a) to step (b)). (For voltage
voltage in the sensed phase only
calculations. For voltage regulators
voltage shall be used.)
Convert each of the values obtained
(1) above to a percentage of rated
voltage by dividing by the rated
voltage and multiplying by 100.
expressed in percent.
Repeat paragraph 16-15d(1) above
substituting frequency for voltage.
Compare the results tabulated in
paragraphs 16-15d(1) and
16-15d(6)(c) with the requirements
of table 16-1.
16-16. FREQUENCY ADJUSTMENT RANGE TEST.
General. It is necessary that the frequency of a
generator set be adjustable to provide rated
frequency at various load conditions as required
in certain applications and to synchronize two or
more generator sets for parallel operation.
Apparatus. Instrumentation for measuring load
conditions, field voltage and current, and
ambient temperature shall be as described and
illustrated in MIL-HDBK-705.