Operation of the unit requires a three-phase,
A portion of the generated ac power is rectified
60-hertz, 220- or 440-volt ac external power
to supply 28-volt dc at 750 amperes continuously.
source. It is used both aboard ship and ashore.
The unit is self-contained and requires no
The unit is not self-propelled and must be
external electrical or mechanical sources of power.
towed or manually moved. The four-wheel trailer
It may be towed at speeds up to 20 mph. The
is equipped with tie-down rings, pneumatic tires,
efficiency of the NC-10C is not affected on
and a tow bar in front for towing or manual steer-
inclines up to 15 degrees maximum in any direc-
ing. A mechanically actuated hand brake, located
tion from horizontal. Climatic conditions of
on the front of the unit, is connected to
operation are from 18F to 120F ( 22C to
drum/shoe type of brakes on the rear wheels.
50C) and under relative humidity up to 100
Maximum towing speed is restricted to 5 mph.
percent. It will operate efficiently at altitudes from
The MMG-1A weighs 4,120 pounds. It is 7 feet
sea level to 8,000 feet.
10 inches long, 4 feet 2 inches wide, and 3 feet
The general hazards of high voltage, hot
6 inches high.
cables, noise, noxious gases, and exhaust heat are
Stowage compartments are located at the rear
all applicable to the NC-10C. There is also no
lockout circuit to prevent moving the unit with
of the unit for 30-foot ac and dc output cables.
The 30-foot input power cable is stowed in a
the cables still plugged into the aircraft.
compartment at the left front side of the unit.
MOBILE MOTOR-GENERATOR SETS
Control panels and a utility power connector
panel are located under fold-open panels on the
right front side of the unit. A portable floodlight,
Mobile motor-generator sets perform the same
which can be attached to a mounting bracket atop
function as the mobile electric power plants, but
the unit, is stored in a door compartment at the
they are not self-contained and require an external
front of the unit.
source of electrical power for operation. The
MMG-1A and MMG-2 are primarily used in
MMG-2 Motor Generator Set
hangars on shore stations, or on the hangar decks
The MMG-2 is physically quite small and
of aircraft carriers where the running of an
compact. See figure 3-7. It is a trailer-mounted,
able and where external power (220-440/60 Hz)
provide 120/208-volt, 400-Hz ac power, and
is readily available.
28-volt dc power for use in ground maintenance,
MMG-1A Motor Generator Set
The MMG-1A, shown in figure 3-6, is a small,
types of aircraft equipment.
compact, trailer-mounted, electric motor-driven
generator set used to provide 115/200-volt, three-
Mobile air-conditioners are designed to
phase, 400-hertz ac, and 28-volt dc power for
cool, ventilate, dehumidify, and filter the air used
in aircraft cabins and compartments. Although
various types of aircraft systems and equipment.
mobile air-conditioners are usually associated