Section 8: Service; Troubleshooting - Grizzly G0791 Owner's Manual

SECTION 8: SERVICE

Motor & Electrical
Symptom Possible Cause
Machine does not 1. Power supply switched OFF or at fault.
start or a circuit 2. Lathe spindle switch not engaged.
breaker trips. 3. Emergency Stop\RESET button engaged
or at fault.
4. Thermal overload relay has tripped.
5. Wall fuse/circuit breaker is blown/tripped;
short in electrical system; start-up load too
high for circuit.
6. Fuse has blown in machine electrical box.
7. Contactor not getting energized/has burned
contacts.
8. Wiring is open/has high resistance.
9. Motor/plug wired incorrectly.
10. Mill FWD/REV switch at fault.
11. Start capacitor at fault.
12. Motor is at fault.
Motor stalls or is 1. V-belt(s) slipping.
underpowered.
2. Run capacitor at fault.
3. Plug/receptacle at fault.
4. Gearbox at fault.
5. Contactor not energized/has poor contacts.
6. Motor bearings at fault.
7. Motor at fault.
Loud, repetitious 1. Pulley set screws or keys are missing or
noise coming from loose.
lathe at or near the 2. Motor fan is hitting the cover.
motor.
Motor overheats. 1. Motor overloaded.
Motor is loud when 1. Excessive depth of cut or feed rate.
cutting, or it bogs 2. Spindle speed or feed rate wrong for
down under load. cutting operation.
3. Cutting tool is dull.
Model G0791 (Mfd. Since 9/15)

Troubleshooting

Possible Solution
1. Ensure power supply is ON/has correct voltage.
2. Move spindle lever (Page 6) to engage switch.
3. Rotate button clockwise until it pops out to reset it
for operation; replace if not working properly.
4. Test/replace relay. If relay continues to trip, call tech
support for assistance.
5. Verify circuit is rated for machine amp load;
troubleshoot and repair cause of overload; replace
weak breaker; find/repair electrical short.
6. Replace fuse; determine if overload is due to heavy
operation; ensure power source has high enough
voltage and power cord is correctly sized.
7. Test for power on all legs and contactor operation.
Replace unit if faulty.
8. Check for broken wires or disconnected/corroded
connections, and repair/replace as necessary.
9. Correct motor/plug wiring connections (Pages 98
and 100).
10. Test/replace if necessary.
11. Test/replace if faulty.
12. Test/repair/replace.
1. Tension/replace V-belt(s) (Page 89); ensure pulleys
are aligned and free of oil/grease.
2. Test/repair/replace.
3. Test for good contacts/correct wiring.
4. Select appropriate gear ratio; replace broken or
slipping gears.
5. Test all legs for power/replace if faulty.
6. Test/repair/replace.
7. Test/repair/replace.
1. Inspect keys and set screws. Replace or tighten if
necessary.
2. Tighten fan, shim cover, or replace items.
1. Allow motor to cool; reduce load on motor.
1. Decrease depth of cut or feed rate.
2. Refer to feed/speed charts in Machinery's
Handbook or feed/speed calculator on the internet.
3. Sharpen or replace the cutting tool.
-83-