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 TM 55-1905-219-14-5
3-62.2. VOLTAGE REGULATOR - MAINTENANCE INSTRUCTIONS (Cont).
(2) Operation.
(a) When the engine is not running, the armature contact points of the relay are held away from the stationary points
by tension of a leaf spring.
(b) As the engine starts and the generator speed increases, the current flowing through the shunt winding builds up
until it reaches the value for which the relay has been set. At this point, sufficient magnetism overcomes the armature spring tension,
the contact points close and the current flows to the battery. Then the current which flows through the series winding is in the right
direction to add to the magnetic force holding the armature down and the points closed.
(c) When the engine is slowed down or stopped, the magnetic field is not strong enough to hold the armature down.
The leaf spring pulls the armature away from the core and the points separate, opening the circuit.
CAUTION
The regulator cutout relay contact points must never be closed by hand with the battery connected.
This would cause a high current flow through the units and damage them.
c. Voltage Regulator.
(1) The voltage regulator has two windings on a single core. One is a shunt winding consisting of many turns of fine wire
which, in series with a resistor, is shunted across the generator at all times. The second winding is a field current winding which is
connected between the generator field circuit and ground whenever the regulator contact points are closed. In addition to the core
frame, armature and contact points, the unit has a spiral spring which holds the armature away from the core so the contact points are
touching when the voltage regulator is not operating.
(2) Operation.
When the generator voltage reaches the value for which the voltage regulator is adjusted, the combined magnetic field
produced by the shunt winding and the field current winding overcomes the armature spring tension, pulls the armature down, and
separates the voltage regulator contact points. This introduces resistance into the generator field circuit so the generator field current
and
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