How To Change Oil in Large Motorized Pulleys

How to Change Oil in Large Motorized Pulleys


We supply Motorized Pulley belt conveyor drives, serving equipment manufacturers directly and end users through a network of independent distributors & local service providers throughout the United States and Latin America.


This video explains how to change oil in large motorized pulleys.  These conveyor drives are especially popular in bulk materials handling applications such as mining and aggregate production.  Use this video in conjunction with our growing library of tutorials on how to design and maintain bulk handling belt conveyors.

This tutorial is for users of Rulmeca Motorized Pulleys in bulk material handling applications. The lesson applies to our range of models from 8.5″ to 40″ in diameter. We will cover why Rulmeca Motorized Pulleys contain oil, how to check it, and when and how to change it.

All Rulmeca Motorized Pulleys are supplied with an appropriate quantity of oil, which is shown on the motor data plate as you can see here. The type of oil is specified by our customers. When maintaining a Rulmeca motorized pulley, be sure to match the quantity and specification of the factory supplied oil.

When in doubt, contact Rulmeca Corporation, and give us the product serial number. It can be found on the end of the shaft as shown here. Be sure to take special care when changing oil brands or specifications because of the possibility of oil in compatibility. Contact your local oil supplier for assistance in that matter.

The purposes of the oil are to continuously cool the internal motor while lubricating all gears and bearings. Synthetic, mineral, food grade, low viscosity, and high viscosity oils are all available. Under normal operating conditions, with Motorized Pulleys running constantly at full load, synthetic oil should be changed after each 50,000 hours of operation. While mineral oil should be changed at every 20,000 hours.

To check the oil quantity, use your company’s lockout/tagout safety procedures. Then rotate the pulley until the two oil drain holes are at the four o’clock and 10 o’clock positions. as shown here.  Then remove the lower oil plug. When properly full, the oil level should be approximately at the bottom of the lower hole.

You can either look through the lower hole or use a clean, wooden stick, like a dipstick, to verify that the oil is at the bottom of the lower hole.

To check the condition of the oil, remove an oil sample from the lower hole, and examine its condition. The oil’s cleanliness will always be the best guideline regarding the wear and condition of the gears and bearings, and whether to change the oil immediately or delay the oil change. Note that the actual quantity of oil for a given pulley model and face width may vary with motor power. Therefore, it’s essential to determine the actual quantity of oil required prior to beginning the oil change.

To change the oil, simply rotate the pulley until the oil drain holes are at the six o’clock and 12 o’clock positions as shown here. Then place a bucket beneath the lower oil plug, and remove both oil plugs to drain the oil, and allow the pulley to vent.

To refill the oil, replace the lower oil plug

after wiping off any sludge and residue from the plug magnet,

and wrapping the plug threads with Teflon tape.

Pour an appropriate amount of oil through the upper hole using either an oil fill pump or a funnel and measuring bucket. Finally, replace the upper oil plug after wiping any sludge and residue from the plug magnet, and wrapping the plug threads with Teflon tape.

For tips on checking and changing oil in unit handling applications with small Motorized Pulleys, which are 3″ to 6.5″ in diameter, please refer to our separate training video. We hope you found this short tutorial useful. For more tips on conveyor drive design and maintenance, go to RULMECACORP.COM or subscribe to our YouTube channel. Thank you very much.