Doosan D35S-5 Service Manual page 145

Do not try continually the connection longer
than 10 seconds.
Magnetic Switch Return Test
Pull out the pinion to the stopper position by hand as
battery is connected between "M" terminal of
magnetic switch and body. If pinion returns
immediately when it is released, both coils are
normally functioning.
Do not try continually the connection longer
than 10 seconds.
High current and low rpm.
Torque is not enough strong.
High current and no rotation.
No current and no rotation.
Low current and rotation.
(Torque is not so strong.)
High current and high rotation.
(Torque is not so strong.)
D439E Service Manual
CAUTION
CAUTION
Troubles
Unloading Test
1. Connect starter motor (A), battery (B),
ammeter(C), voltmeter (D) and rheostat (E) as
shown in the following figure.
2. Turn the switch ON with setting the rheostat at
max. If starter motor rotates smoothly, then the
starter motor is normal.
a. The wires should be thick as possible and all
terminals should be tightened securely.
b. If the starter motor operates for a long time,
then the rotation speed drops down because
the battery may be discharged.
Do not operate it longer than 10~15 seconds at
once.
3. If the current and rpm are not in accordance with
the standards, perform troubleshooting as to the
following table.
Possible cause
Metal portion is damaged or oil is polluted
Armature core and pole piece are worn
Armature coil is short
Armature switch is connected to the ground
Armature coil or field coil is connected to the ground
Metal portion is melted
Armature coil or field coil is broken
Brush and pigtail are broken
Poor contact between brush and commutator
Due to the stain or biotite etc.
Poor contact at field coil connection (However, if only
shunt coil is short or poorly connected, rotation will
be high.)
Feed coil is short
143 3. Engine Electrical System (D439E)
CAUTION