Electric Pto Clutch; Coil Resistance Measurement - Toro Z Master Z400 Series Service Manual

ELECTRICAL

Electric PTO Clutch

Purpose
The electric clutch controls the engagement and
disengagement of the Power Take Off (PTO) pulley.
Location
The electric clutch is located on the PTO end of the
crankshaft.
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 wound around an iron core, which
acts like an electromagnet when power is applied. The
friction plate is the only piece that can slide inward and
outward on the crankshaft axis. It is spring loaded away
from contact with the clutch plate. When the clutch is
not energized, the clutch plate rests against the brake
material opposite the clutch plate. When energized the
friction plate is drawn into the clutch plate magnetically
and the two rotate as one component.
Testing
6
If the electric PTO clutch does not engage or is suspect
as the cause of an electrical problem in the PTO circuit,
use the following troubleshooting steps to determine
whether the clutch has failed or another electrical
problem exists.
6-12

Coil Resistance Measurement

1. Disengage the PTO, set the parking brake, turn the
ignition to the "off" position and remove the ignition
key.
2. Disconnect the clutch harness from the main
harness.
3. Set the multimeter or volt/ohm meter to check
resistance (ohms).
4. Connect the meter lead wires to the clutch wires as
shown (Fig. 402).
Fig 402
5. The meter should read around 1.84 ohms (meter
readings may vary). If the reading is above or below
these readings, the field has failed and needs to
be replaced. If the reading falls between 2-4 ohms,
measure clutch current draw.
Z Master Z400 Service Manual
coil resist measure