Mechanical & Electrical Problems
Problem: Machine will not start, restart, or repeatedly trips circuit breaker or blows fuses
Possible Cause
1. No incoming power
2. Overload automatic reset
has not reset
3. Sander trips frequently
4. Building circuit breaker
trips or fuse blows.
5. Loose electrical
connections.
6. Motor starter failure
7. Motor failure
8. Miswiring of the unit.
9. On/off switch failure
Solution
1. Verify unit is connected to power.
2. When sander overloads on the circuit breaker built into the motor
starter, it takes time for the machine to cool down before restart.
Allow unit to adequately cool before attempting restart. If problem
persists, check amp setting on the motor starter inside the
electrical box.
3. One cause of overloading trips which are not electrical in nature is
too heavy a cut. The solution is to take a lighter cut. If too deep a
cut is not the problem, then check the amp setting on the overload
relay. Match the full load amps on the motor as noted on the motor
plate. If amp setting is correct then there is probably a loose
electrical lead. Check amp setting on the motor starter.
4. Verify that sander is on a circuit of correct size. If circuit size is
correct, there is probably a loose electrical lead, Check amp
settings on motor starter.
5. Go through all the electrical connections on the sander including
motor connections, verifying the tightness of each. Look for any
signs of electrical arcing which is a sure indicator of loose
connections or circuit overload.
6. Examine motor starter for burned or failed components. If damage
is found, replace motor starter. If motor starter looks okay but is
still suspect, you have two options: have a qualified electrician test
the motor starter for function, or purchase a new starter and
establish if that was the problem on changeout.
If you have access to a voltmeter, you can separate a starter
failure from a motor failure by first, verifying incoming voltage at
230 +/-20 VAC. If incoming voltage is incorrect, you have a power
supply problem.
If voltage between starter and motor is correct, you have a motor
problem.
7. If electric motor is suspect, you have two options: Have a qualified
electrician test the motor for function or remove the motor and take
it to a qualified electric motor repair shop and have it tested.
8. Double check to confirm all electric connections are correct and
properly tight. The electrical connections other than the motor are
pre-assembled and tested at the factory. Therefore, the motor
connections should be double checked as the highest probability
of error. If problem persists, double check the factory wiring.
9. If the on/off switch is suspect, you have two options: Have a
qualified electrician test the switch for function, or purchase a new
on/off switch and establish if that was the problem on changeout.
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