How To: Clean and maintain your brushless motor

Jun 07, 2013 1 Comment by

Eleven steps for best performance

One of the benefits of brushless motors is that they require very little maintenance, but they should be inspected regularly and cleaned to provide optimum performance. This article details the steps you should take to keep your motor in tiptop shape, as well as provides tips on how to make your motor run cooler. A Novak Super Sport speed control and SS4300 motor are shown here, but the information also applies to most of the rebuildable brushless motors on the market.

1. CLEAN THE CHASSIS AND SPEED CONTROL

After you’ve finished cleaning the chassis, make sure that the speed control isn’t loose. If you can wiggle it easily, remove it and the double-sided tape it’s attached with, and re-install it with fresh tape.

Use an air compressor to blow off the dust and dirt that has accumulated on the chassis and speed control. It’s best to work with a clean car and work space to prevent crud from getting into the motor. If necessary, use an old toothbrush to remove stubborn dirt deposits.

2. INSPECT THE WIRING

Use heat-shrink tubing or liquid electrical tape to repair damaged wire insulation.

Check the speed control for frayed wires and damaged insulation; these can lead to radio interference and, worse, short-circuiting, which can burn up the motor and speed control. Repair damaged wires with heat-shrink tubing or liquid electrical tape.

3. REMOVE THE MOTOR

Wipe the motor thoroughly with a rag. Use a toothbrush to clean the ball bearings.

You do not need to unsolder the motor’s power leads or unplug the sensor harness, but doing so will give you more freedom to work. After removing the motor, wipe it with a rag to remove dust and dirt.

4. DISASSEMBLE THE MOTOR

Brushless motors have very few parts, so it’s easy to take them apart for cleaning. Most are held together by a few screws on the front, back, or sides of the motor case. Remove the screws, disassemble the motor and lay the parts on a clean rag. Be sure you don’t lose any spacers or washers that are used to properly align the motor shaft (and magnets) inside the motor. Also note the order in which the spacers or washers are installed.

5. CLEAN THE MOTOR

Just as with regular brushed motors, dirt can accumulate inside a brushless motor. We do not recommend the use of motor spray to clean the windings inside the motor can (stator). Racers who use motor spray simply make any problems worse. Instead, use a small brush and light air pressure to clean inside the motor.

6. CLEAN THE BEARINGS

Remove the rear bearing from the motor for cleaning. The front bearing on Novak brushless motors is glued to the front endbell and cannot be removed; leave the front bearing in place, and give it a good dousing with motor spray.

KEEP IT COOL

With today’s high-capacity NiMH and LiPo cells, run times longer than 30 minutes are not unusual. But running a vehicle that long can lead to overheating that will cause your speed control’s thermal-shutdown feature to kick in. Check with your motor’s manufacturer because they probably have optional motor-cooling products as well.

Attach a cooling fan to your speed control and it will pass a constant flow of cool air to help regulate running temperatures. You can mount the cooling fan to the speed control’s heat sink, if it has one, or onto the chassis next to the speed control so that it blows directly on the case. Plug the fan’s connector into your receiver’s battery slot; it can also be wired to the speed control. These small fans use very little power, so it will not decrease your run times.

Some motors, like Novak’s Velociti, can be fitted with a motor sleeve that replaces the stock center sleeve in your Velociti or Super Sport brushless motor, and it has tall cooling fins to dissipate heat. This motor sleeve will not fit most 1/10-scale off-road buggies and trucks in which the transmission wraps around the motor. It’s best for on-road vehicles and monster trucks with a lot of room above the motor. The fins are designed to have a fan mounted directly to the heat sink as well. If your motor manufacturer does not offer a motor heat sink you may be able to find a generic one that will fit.

Installing both of these items will significantly lower the running temperature of your motor and speed control. If you use batteries with a capacity of 4800mAh or more, these items are must-haves.

7. INSPECT THE MOTOR

Check the clean and disassembled motor pieces for signs of wear. Make sure that the windings in the can aren’t loose, chafed, or shiny. Check the magnets for rub marks, and make sure they aren’t chipped or loose.

8. LUBRICATE THE BEARINGS

The motor spray washed away the factory-applied lubricant, so you’ll need to re-lubricate the bearings.

9. INSPECT THE BEARINGS

Before you rebuild the motor, check the front and rear ball bearings to ensure that they spin freely. Insert the tip of a pencil into the bearing and use it to rotate the inner race. If the bearing feels gritty, replace it. Check your motor’s instructions, or consult its manufacturer to make sure that you get a replacement of the proper size.

10. REBUILD THE MOTOR

You have cleaned and inspected the motor’s major components and lubed the bearings, and it’s now time to rebuild it.

11. REINSTALL THE MOTOR

Make sure that the gear mesh is set correctly, and use zip-ties to secure the power leads and the sensor wires and to keep them away from spinning parts. Your brushless system is now ready for action.

Pit Tips

About the author

Associate Editor Since receiving my first hobby-grade RC car as a holiday present from my father nearly 20 years ago, I've been fortunate enough to meet more people and experience more opportunities through the adventures I've had in the RC industry than I would've ever imagined. I've done it all - from working at a hobby shop, to being a factory sponsored racer, to working for some of the biggest brands in the industry. I've enjoyed each and every one of the dozens of kits I've built, hundreds of events I've attended, and thousands of laps that I've logged at race tracks around the world, and my passion is to share those experiences with other hobbyists so that they may find fulfillment in their own RC careers.

One Response to “How To: Clean and maintain your brushless motor”

  1. Ron Laisle says:

    If you are going to add an after market heatsink to your motor you will want to take off any labeling,paint or anodizing on both the motor and the heatsink. These will only block the heat transfer and make the motor run hotter than it was before you added the heatsink. Before you install the heatsink apply a THIN layer of thermal paste like is used in a computer. This will guarantee you have the most cooling possible.

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