View Full Version : Electric Motor Brush Basics


hankster
11-07-2005, 01:22 AM
One of the best ways to extent the life of your motor and keeping it running at top performance is by paying attention to the motor brushes. The brushes are the lifeline of the motor and with use they get worn and burnt. If you don't clean and change your brushes often your motor will perform poorly and will have a much lower then expected lifetime.

Brushes are easy to clean and change, are inexpensive and can triple (or more) the life of your motor. Follow along as we give you a few tips on brushes, how to clean them and how to change them.

The motor brush is held into the motor by the brush spring. It is easy to remove the spring by unhooking it from the tab on the brush hood and then removing it from the spring post. Be careful that you do not lose the spring as it can fly off when removed and you will need to use it again when you are done cleaning or replacing the brush.

hankster
11-07-2005, 01:23 AM
Here you can see that the end brush spring has been removed from the spring tab. You can just use your finger to remove the end of the spring from the tab.

hankster
11-07-2005, 01:24 AM
The brush spring has now been removed from the brush and the brush easily slides out of the brush hood. It is best to completely remove the brush spring from the motor and put it in a safe place so you do not lose it. It is just kept on the spring post here for illustration.

hankster
11-07-2005, 01:26 AM
The brushes are attached to the brush hood by two different methods. On most stock motors, the brush is equipped with an eyelet and this is held in place by a the brush hood screw. Just remove this screw and you can completely remove the brush from the motor.

On high performance or team motors, the brushes are soldered to the brush hood. You will need to use a soldering iron to remove and replace brushes that are attached this way. If you are not racing in competition, you can replace a soldered on brush with a brush that has an eyelet to make subsequent brush changes easier and it will make little or difference in the speed of your motor.

hankster
11-07-2005, 01:27 AM
Here you can see a brush that has been used next to a new brush. Note that the used brush is shorter and shows signs of burning along the edges. This used brush is not so bad and can be cleaned and reused.

hankster
11-07-2005, 01:28 AM
I like using a Parma Fiberglass Comm Cleaning Stick (part #11050) to clean brushes. It is inexpensive and does a great job. Just use the end of the stick on the face of the brush to clean off the glaze and any deposts.

You can see the difference before and after you are done cleaning the brush. In the top (Before) picture you can see the face of the brush is shiny and glazed. This causing acing and heat buildup which will quickly ruin your motor. The bottom (After) pictures shows a "matte" finish on the brush with the glazing removed. The brush is now ready to be used again.

hankster
11-07-2005, 01:29 AM
Now is a great time to clean the motor. Use can use the same Parma Comm Cleaner stick to clean the comm on the motor. Just stick the cleaning stick in the brush hood, apply a little pressure to the end of it and spin the motor a few times. You may want to put a pinion gear on the end of the motor to make it easier to spin. Use a motor cleaner spray to completely flush out the motors making sure you get the bearings clean of any dirt and gunk. Be sure you use motor spray designed for RC use and to wear safety glasses to prevent the spray from getting into your eyes.

With just a few turns of the motor, the comm is now shiny and ready to go. If your comm is extra worn and gouged, then the comm stick will not completely clean it up. It would be best if you could find someone to "turn" the comm for you. In all cases, it is better to use the comm cleaning stick no matter how bad of shape the comm is in.

Put a drop or two of oil on each bushing on the ends of the motor and you are ready to reinstall the brushes and springs, put the motor back in your car or truck and go out and have a blast!

hankster
11-07-2005, 01:31 AM
End of article. Your comments are welcome.