Belt Drive Drum Fan Pulley Replacement Guide

Quick Answer

Replace the pulley on a belt drive drum fan by first disconnecting power, then removing the belt, loosening the pulley setscrew, and sliding the old pulley off the motor shaft. Install the new pulley, align it with the fan pulley, and retighten the setscrew.

Step-by-Step Pulley Replacement

1. 1. Disconnect Power: Unplug the fan or turn off the circuit breaker. Verify power is off with a voltage tester. Never skip this step—even a switched-off fan can have stored charge in the capacitor.
2. 2. Remove the Belt: Loosen the motor mounting bolts to release belt tension. Slide the belt off both pulleys. If the belt is cracked or frayed, replace it now to avoid future failures.
3. 3. Remove the Old Pulley: Locate the setscrew on the side of the pulley. Use a hex key (usually 3/16 inch or 5 mm) to loosen it. Slide the pulley off the motor shaft. If stuck, apply penetrating oil and wait 5 minutes. Mark the shaft position with a pencil before removal to simplify alignment of the new pulley.
4. 4. Install the New Pulley: Slide the new pulley onto the motor shaft to the same depth as the old one. Tighten the setscrew firmly against the shaft's flat spot. Overtightening can strip the setscrew or damage the shaft. Use a torque of about 5-7 ft-lb.
5. 5. Align the Pulleys: Place a straightedge across the faces of both pulleys. Adjust the motor position until the straightedge touches both pulleys evenly. Misalignment causes belt wear and noise. Check again after tensioning the belt.
6. 6. Tension the Belt and Test: Slide the belt onto both pulleys. Tighten the motor mounting bolts until the belt deflects about 1/2 inch when pressed midway between pulleys. Reconnect power and run the fan for 2 minutes. A belt that is too tight can damage bearings; too loose causes slipping. Adjust if you hear squealing or see wobble.

Product Facts

• Motor and 2 In. Pulley for 36 In. and 42 In. Belt Drive Drum Fans: This 2-speed belt drive motor includes a 2-inch pulley pre-installed on the motor shaft. The pulley is already mounted and aligned, saving you setup time and ensuring compatibility with 36-inch and 42-inch Maxx Air drum fans.