Jacobsen AR3, Technical/Repair Manual

Page: 90 / 342

ELECTRICAL
4181384 First Edition 4-33
4
Run Circuit—Theory of Operation
Power Circuit
Unswitched power is available to key switch terminal 30.
When the key switch is turned to the run position, current
flows from the AC terminal of the key switch through
10-amp fuse F10 to control module terminals 3 and 8,
powering up the module. With the control module
powered up, the control module now provides 5 volts to
the seat switch and park brake switch.
Run Circuit–On Seat
When the operator is on the seat, the seat switch
contacts close. With the seat switch contacts closed,
voltage is provided to control module 5V seat switch
input, activating the input. With the input activated,
current flows from control module 12V fuel shutoff output
terminal 10 through the brake release safety switch to the
hold-in side of the fuel shutoff solenoid, energizing the
solenoid. With the solenoid energized, fuel is allowed to
flow to the engine.
The control module will de-energize the fuel shutoff
solenoid if the operator should leave the seat under the
following conditions:
• The park brake switch is in the released position.
• The park brake switch is in the locked position and
the drive pedals are not in their neutral positions.
The control module will de-energize the fuel shutoff
solenoid approximately 1.5 seconds after the seat switch
contacts open. The time delay is to compensate for
operating the machine over rough terrain.
Diode module V1 conducts to ground the reverse voltage
generated when the fuel shutoff solenoid is de-energized.
Run Circuit–Off Seat
Before leaving the seat, the operator must place the park
brake switch in the locked position and make sure the
drive pedals are in their neutral positions.
With the park brake switch in the locked position and the
neutral switch in the neutral position, voltage is provided
to the control module 5V park brake switch input,
activating the input. With the input activated, current
continues to flow from control module 12V fuel shutoff
solenoid output terminal to the hold-in side of the fuel
shutoff solenoid, allowing the engine to continue to
operate when the operator leaves the seat.
Brake Release Safety Switch
When the park brake release valve lever is placed in the
released position, the brake release safety switch
contacts open. With the switch contacts open, current is
prevented from flowing to the hold-in side of the fuel
shutoff solenoid, de-energizing the solenoid. This
prevents the engine from running until the brake system
is placed back into operation.