(b) Connect the frequency meter to one of
the armature coils of the generator.
(c) Provide separate excitation for the
(a) Start and operate the generator at rated
frequency and at no load.
(b) Adjust the excitation so that any one of
the coil voltages is at rated value.
(c) Read and record the generator frequency
(speed) and the voltage of each armature coil.
d. Generator with separate excitation
(1) Determine from the data obtained in 16-13d.
(2) the maximum and minimum armature coil voltages.
(2) The voltage unbalance is the difference be-
tween the maximum and minimum armature coil
voltages. To express this in percent divide this
difference by rated armature coil voltage and multiply
(a) Start and operate the generator set and
allow the set to stabilize at rated load, rated voltage
and rated frequency.
During this period record all
instrument readings including thermal instrumenta-
tion at minimum intervals of 10 minutes. If necess-
ary, adjustments to the load, voltage and frequency
may be made to maintain rated load at rated voltage
Adjustments to the voltage and fre-
quency shall be limited to those adjustments avail-
able to the operator, specifically adjustments to the
voltage or frequency adjust devices. On sets utili-
zing 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 the data sheet at the time of
Stabilization shall be considered to have
occurred when four consecutive voltage and current
readings of the generator (or exciter) field either
remain unchanged or have only minor variations
about an equilibrium condition with no evident contin-
ued increase or decrease in value after the last ad-
justment to the load, voltage, or frequency has been
Voltage Unbalance (Coil), in percent =
(3) Compare the results of step (2) above with
16-14. Regulator Range Test.
a. General. The voltage adjust device associated
with the voltage regulator provided with the generator
set must have adjustment capable of varying the reg-
ulated voltage throughout the limits and under the
various load conditions and temperature ranges with-
out causing the voltage droop of the set to exceed
The voltage adjust device also
must be capable in some cases of providing an oper-
ating voltage other than rated voltage for special
types of equipment and to compensate for external
Instrumentation for measuring
load conditions, ambient temperature, and the
generator field (or exciter field) voltage and current
shall be as described and illustrated in MIL-HDBK-
c. Preparation for Test.
(1) Preparation for test.
(a) Connect the load and field instrumenta-
tion in, accordance with the applicable figure of MIL-
HDBK-705, Method 205.1, Paragraph 205.1.10 for
one voltage and frequency.
(b) No further adjustments shall be made to
any set control for the remainder of this test except
the control panel voltage adjust device.
(c) Record all instrument readings.
(d) Remove load.
(e) Record all instrument readings (after
(f) Adjust the terminal voltage to the maxi-
mum specified value.
(g) Record all instrument readings.
At voltages above rated values, the
generator will be supplying less than
rated current; and at voltages below
rated values, the generator will be
supplying greater than rated current.
Caution should be taken to avoid
damage to instrumentation and load
(h) Apply rated load (rated kw at rated power
(i) Record all instrument readings (after
(j) Remove load and adjust voltage to the
maximum attainable value or to a value just prior to
actuation of the overvoltage protection device.