Industrial DC motor rotation?

Question

After changing (8) brushes in an industrial DC main drive motor, the motor ran in the wrong direction after power-up...

There are 4 sets of double-brush assemblies (accessible through 2 doors on the motor frame). Access to all 8 brushes requires rotation of the brush assembly mounting ring inside of the motor housing.

The axial position of the mounting ring was refence-marked before brush change-out, and referenced again after brush assembly...

What would make the motor run backwards upon power-up?

Answer 1

Two basic types of DC Motors.

1. Permanent Magnet

2. Wound field

With 4 sets of double brushes, it is possible the wires got switched.  Go to the main drive control and locate the armature wires.  Reverse them.  OR find the field wires if it is a wound field motor and reverse them.  Do not reverse both or the motor will continue to run backwards.