0002
TM 1-1740-221-13&P&P
EQUIPMENT DESCRIPTION AND DATA - (CONTINUED)
ELECTRICAL SYSTEM
Battery. The batteries are conventional 12-volt maintenance free type with a positive cable and a negative ground
cable. The batteries are connected in parallel. Each battery has a minimum 800 CCA. The cables have protective
boots at the battery end.
Alternator. Electrical power is supplied by a belt-driven 90 amp alternator mounted on the front of the engine. It
produces three-phase alternating current and voltage, rectiied to DC. The alternator does not require a cutout relay.
A current regulator is part of the alternator assembly. It determines output current according to load, such
as headlights, rear lights, etc.
Starter. A starter lockout switch prevents starter and ring gear damage when engine is running. Tractor starts
only in Park. All circuits are protected with circuit breakers and/or fuses.
The starter motor is a gear reduction type and is used to turn the engine fast enough to start the engine.
Lights and Accessories. Two headlights are on the front of the tractor. The stop/tail lights and rear backup lights
are in the rear body. The backup lights can also be used as work lights (there is a separate switch for this purpose).
Turn signal lights are below the headlights on the front and combined with taillights on the rear.
DASH PANEL
The dash panel is a NEMA 4, rain tight enclosure with automotive type instrumentation. Indicator lights are
provided to give visual status of various operations and functions. A rotary dimmer switch allows varying the back
light intensity of the instrumentation. Indicator lights are "iris" adjustable type to vary the intensity of the light.
AXLES
Front and rear brakes are driven and contain wet disc packs for service brakes. Front axles are steerable.
BRAKE SYSTEM
Service Brake. Brakes are four wheel service brakes. Dual brake system serves front and rear wheels
independently. In the event of an engine failure, braking is still by application of the service brake pedal.
The brake pedal is located on the loor, to the right of the steering column. The service brakes, both front and
rear, are "wet" disc type, fully enclosed and oil cooled. They will withstand repetitive use without excessive fading,
provide short stopping distances, and are spark free.
Parking Brake. The parking disc brake is located on the transmission output shaft. It is applied manually with the
park brake lever. The park brake should always be applied and released as required. An indicator light on the dash
will come on whenever the parking brake is applied.
STEERING SYSTEM
The system is hydraulically assisted orbital and uses a single hydraulic cylinder built into the front axle to pivot
the wheel hubs. A hydraulic reservoir is provided for hydraulic oil supply and an engine driven pump provides
hydraulic pressure.
In case of engine failure, emergency steering is manual only, and will only be possible if the tow tractor is rolling.
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