ARMY TM 9-6115-673-13&P
AIR FORCE TO 35C2-3-512-1
The ON-OFF load circuit breaker
to take the generator set off line
in an overload condition.
circuit breaker is located on the right side of the main control panel. A circuit interrupter, internal to the circuit
breaker, is connected between the alternator output and the generator set output terminals to disconnect the
generator output from the load and also to protect the generator from a short circuit. The circuit interrupter is
operated from a current sensor internal to the circuit breaker.
d. Transient suppressors (MEP-501A) protect the load circuit from potential damage caused by cross-
connecting the + and - output terminals of the alternator. The transient suppressors are located in the main
DIFFERENCES BETWEEN MODELS.
1.14.1 The differences between models of the generator sets covered in this manual are as follows. Refer to
a. Model MEP-531A is equipped with a 120 VAC, 60 Hz alternator.
b. Model MEP-501A is equipped with a 28 VAC alternator rectified for DC output.
1.14.2 This manual is written primarily for the Dewey configuration of generator sets. The differences between
(MEP-531A and MEP-501A) models of generator sets and those built by Mechron are as follows:
a. Fuel Tank.
Mechron sets do not include a fuel drain cock.
b. Fuel Filter Assembly.
Air Force Mechron sets have a different fuel filter head with shutoff valve and bleed screws facing the
engine. Army Mechron sets were issued a replacement which matches the Dewey configuration.
c. Low Oil Pressure Switch.
Air Force Mechron 28 VDC sets do not include a coupler on this switch. Army Mechron 120 VAC sets have
a new standard-to-metric coupler.
d. Convenience Receptacle.
Mechron 120 VAC sets were issued without a Ground Fault Circuit Interrupter feature on the
receptacle. This receptacle should be discarded and replaced.
e. Component and Wire Labeling.
Labeling differences do exist. Cross-reference tables for components and wiring identifiers are
provided in Appendix J for the Mechron sets. Schematic and wiring diagrams are provided for both
MEP-531A/501A and Mechron sets in Figures FO-1 through FO-6.