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Old 12-07-2008, 11:21 PM   #1 (permalink)
TomEV
Ford Escort 2.0
 
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Join Date: Feb 2008
Location: Alameda, CA
Posts: 240

Electricar - '89 Ford Escort LX Hatchback
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Motor Brush Advance

Anyone ever changed the brush advance on their series motor? Did it change performance or effeciency?

The other day I was inspecting the motor brushes on my Citicar (3.5HP GE) and noticed that the brushes appeared to be set 'after' the stator center line. From what I've read, the brushes are factory set to zero for a bi-directional motor, but can be set advanced for a motor that doesn't see high speed in reverse.

After I took the motor out, measurements confirmed that the brushes were indeed set after the center line. Oddly enough, the brush block assembly was angled 'into' the normal forward rotation - they should be angled away.

Third oddity - when the motor is wired normally (A1 and S1 same polarity, A2 and S2 the other polarity) the motor turns in reverse. Not a big deal (just swap S1 and S2) but still strange.

All together, makes me believe that this motor was designed to turn in the other direction, and is less than optimal when operated in 'reverse' to make the Citicar (with a Terrell axle) go forward.

Not much I can do about the brush block angle (without changing a bunch of rivets...) so I drilled and threaded two additional holes in the motor center case to change the brush advance. The brushes were retarded 5 or so degrees before the change, and they are now advanced about 5 degrees.

The motor still moves the Citicar, but I'll have to wait a few days to see how it runs... hopefully better! Front brakes are currently awaiting a new set of shoes...

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