This video will walk you through how to check the relative polarity of DC machine interpoles and the armature and correct it if necessary using a simple interpole polarity test.

It's important to perform this test after any DC machine repairs or routine maintenance activities where the brush lead to the brush holders might accidentally be switched. If undetected, this will cause severe brush sparking or even flashover as the motor is loaded.

Some topics covered include:

• How to verify whether or not the intpole polarity is correct
• How to diagnose and remedy Interpol polarity problems, including misconnected or incorrectly sequenced inner poles
• How to check for too many or too few interpol circuits

The video also has bonus tips about equalizing jumpers.