Motor EMI shielding

I am using the “37D mm metal gearmotors with encoders and end caps” on my custom robot. My robot is also using sensors to detect an invisible dog fence radio signal. When I drive the motors, a lot of noise is picked up by my sensors. I have found that surrounding my sensors with steel sheet metal can block the noise while the motors are driving. This proves to me the source is EM radiation from the motors or from the wires powering the motor. Do you have any suggestions for how I should attenuate this noise? Is the noise source more likely to be the wires or the motors? If it helps to know, my sensors are designed to detect an 11kHz radio signal.

Hello, Chris.

We have some general suggestions for dealing with motor noise in this application note. It is difficult to say whether the motor or wiring is causing more of the noise your sensor is detecting as the proximity of the components in the system can make a large difference. Also, the noise generated by the wiring and the motors can be inter-related and some of the suggestions in that application note (like adding capacitors to the motor) might reduce the noise generated by both.