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 Speeed 400 Motor Break-In

(& similar DC brush motors)

 NOTE: this method should NOT be used if your motor uses a ball-bearing supported shaft

Also note: this method is NOT recommended for Kyosho Magnetic Mayhem motors

& other brush DC motors using pre-shaped brushes



In the following illustration you see two motors. The motor on the top is new - the brushes on new motors are flat where they contact the commutator. When a flat brush contacts a cylindrical commutator, the contact area between these two objects is very small.


In order to improve the contact area between the brush and the commutator, motors should be "broken-in", which means the brushes will be worn down to match the shape of the commutator. Every DC brush motor should be "broken-in" before being used to fly a radio controlled airplane. There are several reasons for this. Following is a partial list of reasons why DC brush motors should have their brushes worn to the shape of the mating commutator before being used to fly an airplane:


The motor will run with greater efficiency

The motor will run cooler

The run times will be longer

The motor will provide more power

The life of the motor will be longer

Less Arcing, hence less radio interference





Okay, I realize it's important for me to break in a motor, so,

how is this done?

Get the following:



Here's what you should do:

1 - Take the batteries in series (you could tape them together), to provide a 3 volt DC source.

2 - Put the motor in the cup of water, making sure it's fully immersed.

3 - Add a drop of liquid dishwashing detergent

4 - Take the wires & connect the motor directly to the batteries, running the motor in the reverse direction for about 5 minutes

5 - Take the wires, then reverse the polarity of the power supply and run the motor for five minutes in the normal direction.

6 - Remove the motor from the cup of water & while the motor is running, shake out water from the inside of the motor. Terminate the power supply (stop the motor) & remove as much water from the motor as possible.

7 - Lubricate the front & end bushings (sleeve bearings) with a tiny drop of light oil (like 3-In-1 oil, or similar). Wipe off any excess oil.

That's it! Now, your motor is ready for action!!!


In this photo, I'm using a battery holder with two AA alkaline batteries (other battery is behind the first one, on opposite side of holder) - you could also tape your batteries together. Running the batteries in series, this provides a safe, 3 volt DC source - perfect for wearing down a new set of brushes. Running the motor under water serves the following purposes:

* The brush residue/dust is taken away from the inside of the motor

* The motor runs cooler under water

* The water provides higher resistance while the motor is running