4-48. MAGNETIC MOTOR STARTER OVERLOAD RELAY HEATER.
General. An overload relay, with a relay heater, is mounted to each side of each magnetic motor starter. The
overload relay heaters prevent damage to equipment in case of overload in the circuit. All overload relay heaters are
removed and replaced in the same manner.
Before connecting to external power source, make sure all power controlling switches are off and the truck
chassis is grounded. Never handle live electric wiring. High voltage may cause serious injury or death.
Removal. Remove two mounting screws (6, fig. 3-12) from overload relay heater (7) and pull straight out on
heater to remove it from overload relay (5).
Inspection. Inspect heater for cracks, burned or broken wires or damaged insulation.
Replace. Replace an unserviceable overload heater.
Installation. Position overload relay heater (7, fig. 3-12) in overload relay (5), and secure with two mounting
screws (6) and lockwasher.
4-49. MOTOR STARTER-OPERATING COIL.
General. The magnetic starter operating coils are located on the magnetic starters between the overload relays.
When current flows through the coil it creates a magnetic field and causes the motor starter to engage.
Remove terminal screws (1, fig. 3-12) from operating coil retainer (2) which holds the wires.
(2) Pressagainst coil (4) and at the same time pull slightly on coil retainer (2) and move retainers away from
Pull one end of the spring clip (3) forward and slide it out of slot.
Draw movable portion of magnet assembly (8) and coil (4) from starter.
Inspection. Inspect the coil for cracks and damaged terminals.
Replace. Replace the coil if it is unserviceable.
Position coil (4, fig. 3-12) on magnet assembly (8).