TM 5-6115-465-34
T0 35C2-3-446-2
NAVFAC P-8-625-34
TM06858B/06859D-34
% Regulation =
MIL-HDBK-705, Method 205.1, paragraphs 205.1.10,
(No-Load Voltage) -(Rated-Load Voltage) x 100
for one voltage and frequency. Connect the signal
(Rated- Load Voltage)
input of the recording meter(s) to the convenience
receptacle of the set or to the generator coil which is
e. Results. The data sheets shall indicate the
used as the voltage sensing input to the voltage regu-
voltage regulation as a percent of rated voltage with-
later. (Power the recording meter(s) from the
in the specified limits at the minimum and maximum
commercial utility. )
specified voltages and the regulation as a percent of
rated voltage at the extremes, the maximum and
(b) Set the recording meter chart speed(s)
minimum voltages attainable and the actuation of the
to a minimum of 5 inches per hour, The following
protection devices (if applicable). Compare these
items shall be recorded on both the data sheets and
results with the requirements of table 7-1.
recording chart(s):
7-15.
FREQUENCY AND VOLTAGE REGULATION,
1.
The date
STABILITY , AND TRANSIENT RESPONSE
2.
The serial number(s) of the record-
TEST (SHORT-TERM).
ing meter(s)
3.
Generator set identification
a. General. The frequency regulation (some-
4,
The recording chart speed(s)
times referred to as droop) of a generator set is the
5.
The data reading number
maximum difference between the no load value of
frequency and the value at any load up to and includ-
(c) Place all instrumentation referred to
ing rated load. This difference is expressed as a
in paragraph 7-15b. in operation.
percentage of the rated frequency of the generator
set. The voltage regulation is expressed similarly
(2) Test.
except that the rms value of voltage is used.
(a) Start and operate the generator set and
Frequency stability describes the tendency of the
allow the set to stabilize at rated load, rated voltage
frequency to remain at a constant value. Generally,
and rated frequency. During this period operate the
the instantaneous value of frequency is not constant
recording meter(s) at a chart speed of not less than
but varies randomly above and below a mean value.
6 inches per hour, and record all instrument readings
Stability may be described as either short-term or
including thermal instrumentation at minimum inter-
long-term depending upon the length of time that the
vals of 10 minutes. If necessary, adjustments to the
frequency is observed. Another term, bandwidth,
load, voltage and frequency may be made to maintain
describes the limits of these variations. Bandwidth
rated load at rated voltage and frequency. Adjust-
is expressed as a percentage of the rated frequency
ments to the voltage and frequency shall be limited to
of the generator set. Voltage stability is described
those adjustments available to the operator, specifi-
similarly.
cally adjustments to the voltage or frequency adjust
devices. On sets utilizing a droop-type speed control
Frequency transient response describes the reaction
droop portions of the control may be adjusted. No
of the frequency to a sudden change in some condition;
other adjustments to the voltage and frequency control
such as, a load change on a generator set. This re-
systems shall be made. Adjustments to load, voltage
sponse consists of the amount of excursion beyond the
or frequency controls shall be recorded on both the
mean of the new operating band, and the recovery
data sheet and the recording chart(s) at the time of an
time. The recovery time is the interval beginning at
adjustment. Stabilization shall be considered to have
the point where the frequency leaves the original
occurred when four consecutive voltage and current
prescribed operating band and ending at the point
where it enters and remains within the new prescribed
either remain unchanged or have only minor varia-
operating band. The amount of surge is expressed
tions about an equilibrium condition with no evident
as a percentage of the rated frequency of the genera-
continued increase or decrease in value after the last
tor set. The recovery time is expressed in seconds.
adjustment to the load, voltage or frequency has been
The voltage transient response is described similarly.
made.
b. Apparatus. Instrumentation for measuring
(b) After stabilization has occurred, drop
load conditions, field voltage and current, and ambient
the load to no load and reapply rated load a number
temperature shall be as described and illustrated in
of times (three should be sufficient) to assure that the
MIL-HDBK-705, In addition, recording meter(s) for
no load and rated load voltage and frequency values
recording voltage and frequency shall be required.
are repeatable and that the frequency and voltage
regulation is within the limits specified in the pro-
c.
Procedure.
curement document. If any adjustments are neces-
sary, paragraph (a) above must be repeated. Reapply
(1) Preparation for test.
rated load.
(a) Connect the load and field instrumenta-
(c) The recording meter chart speed(s)
tion in accordance with the applicable figure of
shall be 12 inches per minute throughout the remainder
7-8
