Service manual

Groundsmaster 3280−D/3320Page 6 − 20Electrical System
P.T.O. Electric Clutch
An electric clutch is used to engage the P.T.O. The elec-
tric clutch is mounted on the engine crankshaft and en-
gages when current is applied to the clutch. The clutch
also incorporates a magnetic brake to stop clutch rota-
tion when the clutch is de−energized.
Testing
1. Park machine on a level surface, lower cutting deck
(or implement), stop engine, engage parking brake and
remove key from the ignition switch. Raise hood.
2. Locate electric clutch on engine crankshaft (Fig. 25).
Unplug clutch connector from machine wire harness.
3. For accurate clutch resistance measuring, clutch
should be at approximately 70
o
F (21
o
C).
NOTE: Prior to taking small resistance readings with a
digital multimeter, short the meter test leads together.
The meter will display a small resistance value (usually
0.5 ohms or less). This resistance is due to the internal
resistance of the meter and test leads. Subtract this val-
ue from from the measured value of the component you
are testing.
4. Using a multimeter (ohms setting), verify clutch coil
resistance between the two terminals of the clutch wire
connector. Coil resistance should be approximately 3.0
ohms. Additionally, check that there is no continuity be-
tween either of the clutch wire connector terminals and
the clutch frame.
5. Using access slots in clutch cover, measure gap be-
tween clutch rotor and armature (Fig. 25). Gap should
be from .012” to .024” (.3 to .6 mm) at all three access
slots. If gap is incorrect, loosen or tighten three (3) lock
nuts evenly to achieve correct, uniform gap.
6. As an additional test, apply 12 volts to the terminals
of the clutch. The clutch should engage. If clutch does
not engage when voltage is applied, replace clutch.
7. If clutch removal is necessary, see P.T.O. Electric
Clutch in the Service and Repairs section of this chapter.
1. P.T.O. clutch
2. Access slot
3. Lock nut
Figure 25
3
1
2