Rebuilt starter spins ant-clockwise

LizardsA

LizardsA

Senior Member
I have rebuilt the starter motor, and when we tried to start the car, the starter motor spins but the Bendix doesn't engage. When we took the starter motor off the car and put it in a vice, attached the battery, and then we saw that it spins the wrong way. What have we done wrong?
Also, are all four brushes meant to touch the commutator?
 
Be sure to check the polarity of your test connections. Must match the vehicle polarity.. is the car positive or negative ground?
Joe B
 
JoeCB said:
Be sure to check the polarity of your test connections. Must match the vehicle polarity.. is the car positive or negative ground?
Joe B
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I'm not sure what is going on here. The starter shouldn't care if it is positive or negative ground. A lot of people switch their car from 6v positive ground to 12v negative ground without changing the starter.
 
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I should have stated that in my initial post - the car is 6 volt positive ground, stock standard as Henry made it.
 
The starter is not polarity sensitive.It doesn't care how it is hooked up.What does care are the field coils.I don't remember if it is the way they are wound,or the way they are hooked up.I've seen this plenty working on trucks and equipment all my life.The most popular truck starter in the world,the Delco 40 MT always have a tag stamped CW or CCW.The armatures that have a machined in spiral gear will be different too.I can tell you that if you put a starter from a bus,(reverse rotation engine) in a Mack it won't run well. Exhaust going out through the air filter,intake air coming in through the muffler,and no oil pressure.
 
Starters are shunt wound for torque but draw high amps. If the fields were removed then I'd investigate how they were wound. Winding them differently can reverse direction of the magnetic fields.
 
I've seen it a lot with starter generators on small engines too.Somebody has one go bad,and they find a used one off a different brand of equipment.A Ford garden tractor might have the pulley on the output side of the engine,and a Cub Cadet might drive off the opposite end with the starter turned the other way.Years ago I put a rebuilt unit on a Cub Cadet for an old guy.He bought the unit exchange from a rebuild shop.It spun over great,but wouldn't start.I put my hand on the exhaust pipe,to make sure it wasn't plugged with mice nests,and it tried to suck my hand in.It was also blowing out the carb.He took it back to the shop he got it from and they told him to hang around.They handed it back to him,all fixed,in a little while.
 
Somewhere in the literature I've seen direction on "flashing" the field. This can end up "inverted" merely in the act of assembly/disassembly.

Try search term here "Flash Field" and you may come to comments prior from those here.

Joe K
 
I believe the fields and brushes being installed 90 degrees off will reverse the motor. Any chance that may have happened when assembling the starter with the new field winding?
 
#7 Yes, a incorrect part made it into your rebuild. Send it back, and HAVE THEM REPAIR OR REPPLACE.
 
Lisards,

the starter motor is a series-connected main current motor. If it rotates in the wrong direction, the carbon brush pairs were accidentally swapped during assembly.
 
I guess the best way to put it is that the model A starter has two separate field groups that are both tied into the same power in terminal with two separate power brushes and two separate ground brushes. It has two north pole shoes opposite of each other and two south pole shoes opposite each other. This makes it very important that the brushes be wired correctly to maintain the proper fields and that the fields be wired properly to maintain proper direction of rotation and proper torque function. The power brushes are opposite each other and the armature ground brushes are opposite each other but they have to be in the correct orientation in the case.

The OP should contact the supplier and make arrangements to get a warranty replacement. Mistakes are far too easy to make during overhaul. The coils are wrapped so they take a careful eye to make sure they are properly placed in the case and that the brushes go where they are intended to go.
 
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The field coils can only be mounted in the case one way in order to solder them to the large round copper terminal that the starter switch activates. So, unless the coils are not wound properly from the factory, I would guess the brushes are placed incorrectly in the brush holders of the front end plate.
 
Thanks to all who offered advice on this. We have found the problem. Following Werner's lead that the brushes were in the wrong place, I took a working starter off my other 'A' and compared the two - voila! the end plate on the one that we were struggling with had the brush holders mounted in the wrong places. Instead of an earth brush holder, we had an insulated holder, so the previous owner had assembled the thing incorrectly, then probably just sold it off on eBay.
Just a correction to all those who think that the end plate can "just be moved through 90 degrees" - impossible, because there is only one way for the long bolts to go through the starter without getting in the way of the wiring and the coils.
At least we now have a working starter, thanks in the main to Werner who put us on the right track of what to look for
 
LizardsA said:
Thanks to all who offered advice on this. We have found the problem. Following Werner's lead that the brushes were in the wrong place, I took a working starter off my other 'A' and compared the two - voila! the end plate on the one that we were struggling with had the brush holders mounted in the wrong places. Instead of an earth brush holder, we had an insulated holder, so the previous owner had assembled the thing incorrectly, then probably just sold it off on eBay.
Just a correction to all those who think that the end plate can "just be moved through 90 degrees" - impossible, because there is only one way for the long bolts to go through the starter without getting in the way of the wiring and the coils.
At least we now have a working starter, thanks in the main to Werner who put us on the right track of what to look for
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And I/we learned something in the process. Thanks for sharing and following up. Too many times this doesn't happen.
 
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