Mitsubishi Electric UM 5t Instruction Manual page 45

Problem
12. The motor overheats
13 Pressing a pushbutton
rattles the contactor.
14. The relay functions, but
the electromagnetic
brake is not released.
The electromagnet will
not attract.
15. The electromagnetic
brake coil has been
burnt out.
16. The electromagnetic
brake does not work
effectively.
17. The traversing brake is
too effective or
ineffective.
18. Rotation with the
traversing brake
applied.
19. The traversing motor
does not have enough
rotation power, or will
not function.
20. The gears make too
loud noise.
21. Traversing wheels spin. (1) The traversing wheel on the driving side is
22. The trolley wheels are
easily disconnected.
Cause
(1) Inching operation is performed too frequently. (1) Apply a special design.
(2) Electromagnetic brake not released.
(3) Operating time long
(4) Overload.
(1) Extreme voltage drop
(1) Too large voltage drop, or too low supply
voltage
(2) Too large core gap
(3) No gap, or gap adjusted too large.
(4) Movable parts catch on something.
(5) Brake circuit cable broken, or screws
loosened.
(6) Brake circuit diode (DC) defective
(7) Coil burnt out.
(8) Too large center clearance
(1) High frequency of uses
(1) Too large core gap
(2) The relay does not function properly.
(3) The electromagnetic contactor cannot properly
cut off the power.
(4) Adhesion of oil to the brake disk
(5) The immediate cut-off contactor does not
operate properly. (Direct current)
(1) Brake adjustment failure
(1) Brake coil wire breakage, or mis-connection
(2) Diode defective, or mis-connection
(3) Too small or large gap
(1) Brake coil wire breakage, or mis-connection
(2) Diode defective, or mis-connection
(3) Too small or large gap
(1) Gears and bearings worn out
lifted due to the inclined I-beam.
(2) Paint, oil, or dust is on the transfer surface of
the I-beam.
(1) The trolley wire has not been stretched as
specified.
(2) The trolley pole has been installed in the
reverse direction.
(3) Wheels not on the same level
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Remedy
(2) See Item 13.
(3) Adopt the same remedies as
Item 10, or do not use the
motor too frequently.
(4) Reduce the load.
(1) Refer to Item 10.
(1) See Items 10 and 11.
(2) Replace the brake disk.
(3) Re-adjust.
(4) Repair.
(5) Check, and repair.
(6) Replace the diode assembly.
(7) See Item 15.
(8) Correct.
(1) Correct the operation method,
and replace the coil.
(1) Replace the brake disk.
(2) Replace the relay.
(3) Check the internal wiring.
(4) Degrease the brake disk, or
replace the brake disk.
(1) Adjust the brake properly
with the adjusting bolt.
Replace, or repair.
Replace, or repair.
(1) Replace.
(1) Install the hoist in the reverse
direction.
(2) Clean, or, if necessary, grind.
Improve.