Small DC Toy Motor (Noise) 1

[yanco]

I would like to know what is the different in between metal contact and carbon contact on the above subject. Why the carbon contact have higher noise and any method to reduce the noise of the motor ?

Any article on the above subject highly appreciated. Thanks.

 

[DougMSOE]

Typically, the carbon will have less noise, if all is well.
But in small motors, proper design of the brush rigging, amps/in^2, etc takes a back seat to the rest of the motor.
Suggest you try (as a place to start) "brush seater" which may be purchased from an electrical supply house.
Also look on the web for Helwig Brushes. A very good company doing only electrical brushes.

 

[jbartos]

Suggestion: If the noise is coming from sparks, then the metal contact can be made more conductive than the carbon contact. Therefore, there might be more noise from graphite brushes. DC motors with higher RPM tend to have it characteristic noise coming from higher RPM and commutator brushes.