Regulator - TM-10-3930-622-140028

the engine starts, the pinion turns faster than the

certain conditions, such as a fully discharged battery

threaded sleeve on the armature shaft and is screwed

being in the circuit, it could generate currant at a rate

back out of mesh with the flywheel ring gear. The

high enough to burn up the armature unless protection

operator controls the starting motor by a button on the

were provided. The current regulator is a normally

instrument housing. The control circuit to the starter

closed relay sensitive to armature current flowing through

includes a neutral safety switch which permits operation

a series coil wound on its core. Generator field current is

of the starting motor only when the truck transmission is

carried across the contacts of this relay. Armature

in neutral.

current flow in excess of a safe value will open the points

to interrupt field current. Field strength will decrease,

c. Generator. The generator is a two-brush shunt

reducing output momentarily, and the points will close

wound circuit A type 12-volt dc generator with external

again under spring tension, to complete the field circuit.

current and voltage limiting regulator. The generator is

The regulator will cycle in this way as long as necessary

belt-driven by the engine crankshaft, pivot mounted in a

to protect the armature. In the instance given, eventually

way that provides for adjustment of the drive belt tension

the battery would be recharged, and at a point in

by positioning the generator on its mountings. The

recharging armature current demand would drop below

generator uses a rotating armature, mounted on

the current regulator setting. At this time the current

bearings at each end. The armature turns in a magnetic

regulator points would remain closed. Note that this unit

field between two pole shoes to induce a voltage in the

is only a limiter of maximum generator current output.

windings of the armature. The induced voltage in the

armature is made available to the external electrical

(3) The voltage regulator. In a general way this

system through two carbon brushes, which both ride on

unit compares in design and function with the current

the commutator of the generator and are connected to

regulator described in (2) above, to limit generator

the external system. Since the electrical system is of the

voltage when demand of the system for current is low,

one-wire type, in which the truck frame constitutes one

and generator operating speed is in the normal engine

side (the ground or negative) of the circuit, one brush of

operating speed range. The voltage regulator is a

the generator is connected to the metal end frame of the

normally closed relay with a shunt coil wound on its core,

generator directly, with no attempt to insulate it. The

sensitive to generator operating voltage. The contacts of

other brush is insulated from the frame at this point, but

the voltage regulator are in series with the contacts of the

is connected to an external terminal (marked A, for

current regulator and carry field current to complete the

armature) on the frame of the generator. A wire from the

field circuit. Note that if these points open, they break

A terminal of the generator to the A terminal of the

the field circuit just as did the contacts of the current

regulator delivers generator output to the external system

regulator, to drop generator output. As with the current

via the regulator. Armature voltage is applied to the field

regulator, when output (in this case voltage) drops spring

windings by connecting one end of these windings to the

tension closes the points and the cycles as necessary to

insulated brush within the generator. The other end of

limit voltage applied to the system to the preset level.

the field windings are led outside the generator to the F

When armature voltage is lower than the value for which

terminal, which is also insulated from the frame. The

the voltage regulator is set the unit operates in a static

field circuit is completed externally by a wire connecting

state only as a section of the generator field circuit.

the generator and regulator F terminals, then through the

(4) Maintenance of the units described above

regulator internal units to ground at the regulator base,

consists of adjustment of the various spring tensions

and through the truck frame back to the armature via the

which govern the values at which the units operate

grounded brush.

electrically, checking and adjusting the magnetic air

d. Regulator. The generator regulator incorporates

gaps, and cleaning or replacing the contact points when

three units, each with its own function, as follows:

necessary.

These procedures are covered at the

appropriate place in this manual.

(1) The cutout, or reverse current relay. This

unit is a normally open relay, sensitive to generator

e. Battery and cables. A 12-volt, lead-acid battery

voltage to close, which will connect the generator

supplies the electrical power to the fork lift truck electrical

armature circuit to the battery and system positive side

system. The battery, mounted in a tray on the vehicle

when the generator voltage exceeds battery voltage, and

frame assembly, is located on the right side of the

disconnect the generator from the system when, due to

engine, directly adjacent to the generator. Two cables, a

slow speed of the armature, its voltage drops below

positive and negative, are used for battery connections

battery voltage. This operation permits charging the

and a negative ground strap is fastened directly to the

battery and operating electrical units from generator

frame.

voltage, while preventing battery discharge through the

1-13. TRANSMISSION ASSEMBLY.

armature windings when there is no voltage in them to

a. The transmission assembly is bolted directly to

oppose battery voltage.

the engine flywheel bellhousing.

The transmission

(2) The current regulator.

The generator

assembly is a single-speed power operated transmission

design permits an output capacity adequate to meet the

normal electrical needs of the system; however, under