TM-9-2920-257-30-P
GENERATOR, ALTERNATING CURRENT, 200 AMPERES
TECHNICAL MANUAL; DIRECT SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS
MAY 1987
TM-9-2920-257-30-P - Page 89 of 111
TM 9-2920-257-30&P
APPENDIX E
TEST STAND PROCEDURES
E-1.
GENERAL
After repair of the generator it must be bench tested to verify
correct operation.
Follow the procedures below to calibrate test
stand tachometer,
set base settings for the test stands, and then
perform tests on the 200 ampere generator/regulator and generator.
E-2.
CALIBRATION
Military vehicle generators are equipped with various size pulleys,
such as 3-, 3 1/2-, and 4-inch diameter.
The 500-ampere test stand
has a 4-inch pulley.
Since the test stand tachometer reads drive head
speed, the tachometer must be calibrated when a generator has a pulley
larger or smaller than 4 inches.
To calibrate the speed of the
generator use fomula below.
Formula: a
= Test speed of test generator (normally lowest rated
output speed as indicated by specifications).
4
= Diameter of drive pulley on test stand.
b
= Value of a x 4.
c
= Diameter of pulley on generator to be tested.
e
= Value of b divided by c (this value will indicate the
speed of the driven pulley when the test stand speed (a) is at
selected speed).
aX4= b = e
c
Example:
To test a generator with a 3-inch pulley, determine lowest
rated speed of generator.
If rated RPM for a generator is 2,000 RPM
to 8,000 RPM, select 2,000 RPM as test speed.
Increase test stand speed to 2,000 RPM with vari-drive speed control.
Turn the calibrate pulley control to calibrate position .
E-1
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