Mitsubishi Electric MDS-B-SPJ2 Series Specification Manual page 159

(20) Alarm No.
[Details] The motor overheated and the motor's built-in thermal protector activated.
When this alarm occurs, the motor cooling fan must be allowed to operate for 10 to 20 min. after
the motor stops before the alarm can be canceled.
Investigation items
1 Investigate
repeatability.
2 Jiggle the speed
detector spindle drive
unit side connector to
see whether it is
coming loose.
3 Check the speed
detector cable
connection.
4 Check between MOH
and RG of the motor
thermal protector with
a tester.
5 Check the spindle load
amount.
6 Check the wiring and
rotation of the motor
cooling fan.
7 Check the finger guard
of the motor cooling
fan.
11. Troubleshooting
46 : MOTOR OVERHEATING
Investigation results
The alarm repeats immediately after
the power is turned ON. Or, the
alarm occurs a few minutes after the
operation.
The alarm occurs after operating for
a while.
Connector came (was coming) loose. Install correctly.
No particular problem.
The connection is faulty.
The connection is normal.
The resistance value is 100Ω or
more.
The resistance value is 10Ω or less.
Frequent starting and stopping. Or,
the cutting load amount is large.
No particular problem.
The motor cooling fan wiring is
incorrect.
The wiring is correct, but the fan
does not rotate.
No particular problem.
The holes on the finger guard are
blocked.
No particular problem.
Investigate item 2, and carry out the
appropriate measures.
Investigate item 5, and carry out the
appropriate measures.
Investigate item 3, and carry out the
appropriate measures.
Correctly connect the cable.
Investigate item 4, and carry out the
appropriate measures.
Replace the motor.
Replace the spindle drive unit.
Decrease the starting/stopping
frequency. Or, decrease the load.
Investigate item 6, and carry out the
appropriate measures.
Correctly wire the fan.
Replace the motor.
Investigate item 7, and carry out the
appropriate measures.
Clean the finger guard.
Replace the spindle drive unit.
11 − 15
Remedy