CM-ET Prostar - Manual (Page 11)

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A. No voltage at hoist.
B. Open control circuit due to loose connections or broken wires in circuit; motor
thermal protector open; control station contacts not closing; open or shorted
winding in transformer; transformer thermal cut-out open; mechanical binding in
contactor; open or shorted winding in contactor coil.
C. Wrong voltage or frequency.
D. Low voltage.
E. Brake not releasing due to open or shorted coil, defective diodes or brake disc
binding.
F. Excessive load.
G. Phase failure (single phasing-three phase units only) - open circuit, grounded or
faulty connection in one line of power supply system, hoist wiring, contactor, motor
leads or windings.
A. Check for blown fuse or tripped circuit breaker or open disconnect switch in main
line or branch circuit. Replace fuse, reset circuit breaker or close switch.
B. Check electrical continuity thru motor thermal protector. If it is open, allow motor
to cool. If this does not correct the trouble, use wiring diagram to check electrical
continuity of wiring, transformer, contactor and control station contacts. Repair
wiring or replace defective part.
C. Make sure that the power supply to hoist is the same as that shown on
identification plate on button of hoist.
D. Check power supply system to make sure it complies with the requirements listed
under “power supply system” starting on page 3.
E. Check coil continuity, diodes (see page11) and connections. Make sure brake
disc slides freely on brake driver and brake spring is not broken. Replace coil
(brake field), repair connections, remove burrs from brake driver so that brake
disc slides freely and/or replace brake spring.
F. Reduce load to capacity limit as indicated on identification and capacity labels on
hoist.
G. Check for electrical continuity and repair or replace defective part.
1. Hook does not respond to control station.
A. Wiring connections reversed in control station or hoist.
B. Failure of cut-out device (single phase units only) to effect dynamic braking at time
of reversal.
C. Phase reversal (three phase units only).
A. Use wiring diagram and check wiring connections.
B. Check connections to cut-out device. Replace damaged device or faulty capacitor.
C. See “Three Phase Hoists” on page 4.
2. Hook moves in wrong direction.
A. Excessive load.
B. Hoisting circuit is OPEN due to loose connections or broken wire in circuit; control
station contacts are not making; open or shorted winding in contactor coil.
C. Motor cut-out device not operating. (single phase units only).
D. Phase failure (three phase units only).
A. See item 1F.
B. Use wiring diagram to check electrical continuity of wiring and control station
contacts. Repair wiring or replace defective part.
C. Check cut-out device and connections to same. See page 11. Repair connections
and/or replace cut-out device.
D. See item 1G.
3. Hook lowers but will not raise.
A. Lowering circuit is OPEN due to loose connections or broken wire; control station
contacts not closing; open or shorted winding in contactor coil.
B. Motor cut-out device not operating (single phase units only).
C. Phase reversal (three phase units only).
D. Phase failure (three phase units only).
A. See item 1B.
B. See item 3C.
C. See item 2C.
D. See item 1G.
4. Hook raises but will not lower.
A. Brake slipping.
B. Excessive load.
A. Check electric brake (see page 9), especially the brake disc for wear or glazing
and make sure brake spring is not broken. Replace worn or glazed brake disc or
replace brake spring.
B. See item 1F.
5. Hook does not stop promptly.
A. Excessive load.
B. Low voltage.
C. Brake dragging.
D. Phase failure or unbalanced current in phases (three phase units only).
A. See item 1F.
B. See item 1D.
C. Check electric brake (see page 9). Check to make sure brake disc is free to move
on brake driver. Check for warped or bent brake disc and base plate. Free-up
brake disc by removing burrs on driver. Replace warped armature base plate or
brake disc.
D. See item 1G.
6. Hoist operates sluggishly.
A. Excessive load.
B. Low voltage.
C Extreme external heat.
D. Frequent starting or reversing.
E. Brake dragging.
F. Motor cut-out device not opening start winding circuit (single phase units only).
G. Phase failure or unbalanced current in phases (three phase units only).
A. See item 1F.
B. See item 1D.
C. Above an ambient temperature of 104°F (40°C), the frequency of hoist operation
must be limited to avoid overheating the motor. Special provisions should be
made to ventilate the space around the hoist and shield it from radiant heat.
D Avoid excessive inching, jogging and reversing. This type of operation drastically
shortens motor cut-out device, capacitor, control station and contactor contact life
and causes excessive brake wear.
E. See item 6C.
F. See item 3C.
G. See Item 1G.
7. Motor overheats (Hoist will not operate in up or down direction - motor thermal protector open).
A. Brake not closing or ineffective. A. Check electric brake (see page 9), and armature for binding, broken brake spring,
first pinion shaft broke, brake driver worn, brake disc worn. Correct binding of
armature; replace broken or worn parts.
8. Hook fails to stop in either direction.
A. Phase reversal (three phase units only). A. See Item 2C.
9. Hook lowers when up button is depressed.
Always disconnect unit from the power supply system before
removing hoist covers or the back cover of control station.
Failure to follow proper lockout/tagout procedures may present the
danger of electrical shock.
TO AVOID INJURY:
Disconnect power and lockout/tagout disconnecting means before
removing cover or servicing this equipment.
––– Probable Cause ––– ––– Remedy–––
TROUBLE SHOOTING