Electric Pto Clutch; Purpose; Location; How It Works - Toro Lawn-Boy TimeCutter Z Series Service Manual

Electric (PTO) Clutch

Purpose

This clutch electrically controls the engagement and
disengagement of the Power Take Off (PTO) pulley.

Location

The electric clutch is located on the PTO end of the
engine crankshaft (Figure 87).
Figure 87

How it Works

The PTO clutch is composed of three major
components; the field, the clutch plate, and the friction
plate. The clutch plate always turns with the engine.
The field is a coil of wire on an iron core, which
becomes an electromagnet when power is applied.
The friction plate is the only piece that can slide up and
down on the crankshaft axis. It is normally spring
loaded so that it is not in contact with the clutch plate
and is pressed against the brake material opposite the
clutch. When power is applied, the friction plate is
drawn toward the clutch plate and the two rotate as
one.

Testing

If the electric PTO clutch is not engaging or is
suspected as a cause of electrical problems, use the
troubleshooting steps. These procedures will help you
determine if the clutch has failed or is the cause of the
electrical problem.
TimeCutter Z Service Manual
ELECTRICAL SYSTEM

Coil Resistance Measurement

1. Disengage the PTO, set the parking brake, turn
the ignition to OFF, and remove the key.
2. Disconnect clutch wire connector.
3. Set the multimeter or volt/ohm meter to check
resistance (ohms).
4. Connect the meter lead wires to the wires in the
clutch connector (Figure 88).
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5. The meter should read between 2.40 ohms and
3.40 ohms. If the reading is above or below these
readings, the field has failed and needs to be
replaced. If the reading is between these two
limits, measure the clutch current draw.

Measuring Clutch Current Draw

1. Disengage the PTO, set the parking brake, turn
the ignition key to OFF, and remove the key.
2. Disconnect the clutch wire connector.
3. Set the multimeter to check amps (10 amp scale).
4. Connect the positive meter lead to the tractor
terminal (1) of the clutch wire, Figure 89.
5. Connect the negative meter lead to the
corresponding wire terminal (3), Figure 89.
6. Connect a short jumper lead from terminal (2) to
terminal (4), Figure 89.
Figure 88
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