Electric Clutch; Checking The Pto Clutch - Gravely Promaster 100 Service Manual

a service center has access to the information and
parts required to test and repair or replace engine
components, including rectifiers and regulators.)
Units that contain both a rectifier and regulator are
tested in a working circuit to make sure the regulator
portion of the device is operating.

13.10 ELECTRIC CLUTCH

The electric clutch is used to turn on and off the
attachment used on the unit by use of a switch. The
clutch is also designed so that a brake is applied to the
output shaft when the clutch is disengaged (off).
The field coil is mounted to a bearing support and does
not rotate. The rotor is attached to the power output
shaft and rotates around the field assembly. The
armature is attached to the output pulley. The armature
assembly is held close to the rotor by the brake
assembly. The clutch is engaged by applying current to
the coil connection. This results in a current flowing
through the coil, magnetizing the coil pulling the
armature onto the rotor with sufficient force to hold the
two pieces together, effectively connecting the output
and the input shafts together. Pulling the armature
against the rotor pulls it away from the brake, releasing
the brake.
Engine Electrical Components
Engine servicing and repair should be referred to local
engine manufactures service centers that have the
service information and parts available to properly
service the engine. Gravely dealers should be able to
test engines and engine components to pinpoint
troubles and narrow them down to properly advise the
engine serviceman.

13.11 CHECKING THE PTO CLUTCH

Measure Clutch Coil Resistance
1. Turn engine and PTO switch off.
2. Disconnect clutch wire connections.
3. Select meter to check ohms.
4. Connect meter leads wires in clutch connector.
5. If meter reads below 2.50 ohms or above 3.50
ohms, then the clutch has failed and needs to be
replaced.
6. If meter reads between 2.50 to 3.50 ohms, proceed
to Measure Clutch Current Draw.
Measure Clutch Current Draw
1. Turn engine off.
2. Disconnect clutch wire connections. Remove 30
amp fuse.
3. Select meter to check amps (10 amp scale).
4. Place meter leads into fuse holder.
5. Sit on the seat to make seat switch connections.
6. Turn the ignition switch to RUN and the PTO switch
to ON.
7. If the meter reads below 4.5 amps, the problem is
in the electrical system leading to the clutch
(Battery, relay, switch wiring).
If you find after measuring clutch coil resistance and
clutch current draw that:
1. The resistance falls between 2.50 and 3.50 ohms.
2. The amp draw is 4.50 or above.
3. The electric clutch is within factory specifications
and is not the source of the problem.
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Figure 30