Yale 11353395D manual Inspection of Motor Brake and Actuating Mechanism

(4)Disconnect the wiring and conduit from the motor junction box.

(5)Provide a means to support the hoist motor. The hoist motor weighs approx- imately 250 lbs. And must be held level while removing and installing.

(6)Once the motor is properly supported, remove the hardware fastening it to the gear case. Carefully withdraw the motor horizontally straight out from the gear case. Do not tip or move the motor from side to side.

(7)Replace the motor shaft seal using an appropriate seal driver. It is recommended that a new seal be installed each time the motor is removed from the case.

IMPORTANT!

(8)Before installing the motor, pack the gear teeth with MPG grease (Paragraph 4-7) and wrap the gear teeth with a number of layers of Teflon tape to protect the seal lip from being damaged by the gear teeth. Coat the seal lip and the motor shaft with MPG grease.

NOTICE

Failure to use a factory replacement seal will cause premature seal failure due to specific lip material requirements that must be met.

(9)Install the motor to the gear case. The motor shaft must be in line with the seal bore and perpendicular to the mounting surface before attempting to insert the shaft through the seal. The motor shaft must remain horizontal and not rock up and down or side-to-side while installing the motor or seal damage will occur. It may be necessary to rotate the rope drum slightly to align the gear teeth to mesh with the teeth on the motor shaft. Ensure that the motor seats properly into the rabbet fit machined in the gear case. Fasten the motor to the gear case.

(10)Reconnect the conduit and power leads to the motor. See Section VIII and refer to the specific wiring diagrams shipped with your hoist.

(11)Refill gear case with lubricant per Section IV, Paragraph 4-2.

(12)Test hoist to ensure proper operation per Section V, Paragraph 5-13.

5-10. INSPECTION OF MOTOR BRAKE AND ACTUATING MECHANISM.

a)General Operation. The hoist brake is an electro-magnetically released, spring set non- adjustable brake. Torque is generated by compressing a friction disk between the stationary motor end bell and the spring loaded brake armature. The friction disk is fixed to the motor shaft and rotates with the motor shaft. When the magnet coil is energized, the armature plate is pulled across the air gap. The friction disk is carried by a splined hub that permits axial movement when the brake is released. This axial movement releases both sides of the friction disk from their mating stationary surfaces and allows the friction disk to rotate freely when the brake is energized. When power is removed from the magnetic coil, the compression springs push the armature against the friction disk and the other side of the friction disk against the motor end bell generating the torque necessary to stop the hoist machinery and hold the load.

It will be necessary to compensate for the friction disk wear when a greater amount of hook movement (drift) is noticed when stopping. There is no torque adjustment of the brake. Friction disk wear can only be compensated for by resetting air gap.

Figure 5-9. Motor Brake.

b)Friction Disk Inspection and Air Gap Adjustment.

(1)Lower hook block to the floor and relieve all load from ropes.

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