TM 5-3805-280-24-2
Group 1677
Starting Motors
GENERAL INFORMATION
IMPORTANT: Never operate starting motor longer
than 30 seconds. Allow at least 2
minutes for cooling and battery
60
recovery before operating again.
05
Overheating caused by excessive
1
operation will seriously damage starting
motor.
RG,RG34710,2335 1915Mar971/1
TYPICAL STARTING CIRCUIT OPERATION
When wire from relay (A) is energized, current flows
through both pull-in winding (C) and hold-in winding (D) to
ground.
Current through windings engages solenoid plunger (E),
which closes main contacts (F). When main contacts
close, current through pull-in windings stops. Current
continues through hold-in winding, keeping solenoid
engaged and main contacts closed.
With main contacts closed, current flows from battery
cable (B) to starting motor at a very high rate. Four heavy
field windings (G) carry current to commutator brushes
A--Wire From Relay
(H).
B--Cable from Battery
C--Pull-In Winding
D--Hold-In Winding
Light shunt windings (J) are wrapped together with two of
E--Solenoid Plunger
the heavy field windings. Shunt windings are connected to
F--Main Contacts
solenoid switch terminal and directly to ground. They
G--Field Windings
provide additional low speed torque to assist engine
H--Commutator Brushes
I--Armature
rotation and prevent overspeeding of motor.
J--Shunt Windings
From field windings, current flows through armature
windings (I) to ground, making contact through
commutator brushes (H).
Strong magnetic fields are set up by current flow through
field windings and armature windings. Windings are
arranged so that magnetic fields constantly repel each
other, rotating armature.
RG,RG34710,2336 1915Mar971/1
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