How to diagnose worn brushes in 2HP brushed DC motor without inspecting?

Oct 08, 2006 1 Replies

Is there an instrument or meter that can be used (and how?) to test for worn out (needs replacement) brushes in a Taiwan-built 2HP brushed motor in an electric scooter?



Also, how many run-time hours before brush failure are typical, in an electric vehicle?



This motor is 24 volts, and the batteries are 35AH. The controller is



100AMP capable, but hasn't been metered for true amp peak.

Thanks in advance for all suggestions.



Brush wear can be affected by many things. A machine where the brushes normally last for six months can suddenly use up a set of brushes in less than one month if conditions change drastically. Shift of the brush rigging out of the electrical neutral; atmosphere contaminants such as hydrocarbon fumes, paint fumes, various aeresols; broken/incorrect spring tension; commutator wear allowing mica fins; overcurrent; undercurrent; flashover;... the list can go on and on...

Chances are, there is some sort of inspection plate that can be opened that will allow a visual inspection. Best rule is to inspect them at about 1/4,

1/2, 3/4 of the expected brush life. There may be some 'telltale' that is meant to allow you to know when they need replacing without having to actually measure them each time. Something like, 'when the brush spring lever reaches "here", the brushes need replacing'.

The manufacturer is your best friend in this.

daestrom

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