How to check the DC motor brushes?

2021-08-23 11:26:33

How to check the DC motor brushes? DC motors are not general equipment for new projects in an industrial environment, but there are still many motors used in pulp, paper and steel customers in the Northwest. DC motors are much more complex than AC induction motors and require regular maintenance to continue to operate at performance. Northwest Automotive Services has a DC motor maintenance program designed to keep these complex motors in peak condition.

The DC motor brushes are in commutation. In a DC motor, the commutator applies current to the armature winding through carbon brushes. Every time the winding rotates half a turn, the direction of the current will be reversed, thereby generating a stable rotating force (torque). Before the advent of variable frequency drives, many DC motors were installed in applications that required speed/process control (used with AC motors). The disadvantage is that carbon brushes are a kind of wear and tear, which should be checked and replaced regularly.

Our DC motor brush maintenance program involves the following items:

 Routine static tests are carried out every year to test the motor windings.

 Check whether the brush is worn and replace it according to OEM specifications.

 Record and record the health status of the commutator and conduct continuous monitoring.

This is a DC motor commutator equipped with brushes. Note the wear on the commutator corresponding to the brush path.

Although this is a relatively simple procedure, we found that many customers lack the resources or knowledge to do this work during a power outage.