GILLIG LOW FLOOR, Руководство по обслуживанию

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Electrical System
375
Starter Solenoid
The solenoid has two windings: the pull-in winding and the hold-in winding. When the starter switch is
closed, both windings are energized, producing a magnetic field which pulls the plunger in. This inward
movement shifts the starter pinion into engagement with the flywheel teeth and also closes the main
contacts in the solenoid switch to complete the battery to starter circuit.
As soon as the main contacts are closed, the pull-in winding is de-energized and only the hold-in wind-
ing draws current and maintains its magnetic field for the duration of the cranking cycle.
The solenoid requires no periodic maintenance other than keeping the terminals clean and tight. Always
check the working of a solenoid which has been removed from service. If the unit fails to function, first
check the wiring. The windings can be checked for current draw, resistance, open circuits, or shorts.
Whenever the solenoid is replaced, the pinion clearance must be checked and adjusted as necessary, as
explained in the “Starter Reassembly” section to follow.
Starter Circuit Diagnosis
Before removing any unit of the starter circuit for repair, the following battery, wiring, and switch
checks, should be performed to help determine which unit is at fault.
1. Battery Check: To determine the condition of the battery, follow the test procedures described
in “Batteries” in an earlier section of this chapter. Be sure the batteries are fully charged. The
wiring, switches, and starting motor cannot be checked if the batteries are defective or dis-
charged.
2. Wiring Check: Inspect the wiring for damage. Inspect all connections to the cranking motor, so-
lenoid, starter relay, switches, and battery, including all ground connections. Clean and tighten all
connections as required. The cranking system cannot operate properly with excessive resistance
in the circuit or loose connections.
3. Switch and Solenoid Check: Inspect all switches and solenoids to determine their condition.
From the vehicle wiring diagram, determine which circuits should be energized with the starting
switches closed. Use a voltmeter to detect any open circuits. A jumper cable can be connected
around any component suspected of being defective. If the system functions properly with the
jumper cable in place, replace the defective unit.
If the batteries, wiring, and switches are in good condition and, 24 volts is present at the starter
input terminal when the starter switch is engaged, remove the starting motor and replace with a
new or Delco authorized remanufactured unit. If you prefer to rebuild the starter at your facility,
consult the manufacturer for instructions.
If the switch, relay, or solenoid shows a voltage loss, replace it. If a more detailed test is desired,
see the following paragraphs.