General. Yale Electric Hoist

SECTION Vl - TROUBLE SHOOTING (Continued)

Trouble

6-4. Hook Will Lower But Not Raise

(continued).

Probable Cause

d. Contactor assembly not functioning.

e. Push button inoperative.

Remedy

d. See that necessary jumper wires are properly installed. Verify that the contactor armatures are free to move. If binding occurs replace contactor. Check for burned out contactor coils.

e. Check push button contacts and wires.

6-5. Hoist Will Not Lift Rated Load.

a. Low voltage b. Overload clutch out of adjustment.

c. Motor brake not releasing.

a. See that power supply is same voltage listed on motor data plate. Check size of power supply lines. Refer to fig. 2-1.

b. Remove and replace clutch assembly. Refer to Section IV, par. 7-2 and 7-4.

c. Check brake components. Refer to Section

VII, par 7-2.d, 7-2.e and 7-2.f.

6-6. Excessive Drift When Stopping.

6-7. Hoist motor overheats.

a. Excessive load.

b. Motor brake not holding.

c. Motor brake not setting due to insufficient plunger air gap.

d. Load brake not holding.

a. Reduce loading to rated load, shown on nameplate.

b. Check brake components. Refer to Section

VII, par. 7-2.d.

c. Adjust air gap. Refer to Section VII, par.

7-11.c.

d. Remove load brake and inspect parts. Refer to Section V, par. 5-4.

a. Excessive load.

b. Excessive duty-cycle.

c. Excessive "jogging." a. Reduce loading to rated load of hoist, shown on nameplate b. Reduce frequency of lift.

c. Reduce frequency of jogs.

d. Wrong voltage.

e. Starting switch on singlephase motors not opening starting winding.

d. Check voltage rating on motor data plate against power supply.

e. Refer to Section VII, par. 7-9.b. (3) (b).

Inspect Switch.

f. Damaged motor or worn f. Disassemble hoist and inspect for worn or bearings in motor or hoist frame.

damaged parts.

g. Motor brake not releasing.

g. Check brake components. Refer to Section

VII, par. 7-2.d.

SECTION VII - DISASSEMBLY AND

REASSEMBLY

7-1. GENERAL.

a. The following disassembly and reassembly instructions apply to all standard models in the line of Yale Electric Hoists equipped with overload clutch. Where needed, variations to instructions are provided to cover differences between models

(suspensions, rated load sizes and motor voltage ratings), with applicable models specifically noted.

b. A complete teardown procedure is given, however, if only certain parts require repair or replacement, a partial teardown may be performed using the applicable portions of the instructions.

c. For easier handling during disassembly, the following disassembly steps may, where conditions permit, be completed before hoist is removed from its overhead suspension or disconnected from its power supply: Remove chain container, if hoist is so equipped; remove lower block and load chain assembly, following procedure outlined in paragraph 7-2. a.

Drain and discard gear case oil, by removing plug at bottom of frame.

d. These hoists contain precision machined parts and should be handled with care at disassembly and at reassembly. When removing or installing parts with press fits, be careful to apply pressure evenly. On ball bearings, apply pressure to face of inner or outer race, whichever is adjacent to mating part. This will avoid damage to bearing races from brinelling by pressing through bearing balls. Apply a thin film of sealant to parts having a press fit when they are installed.

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