electric question

[Pheasant]

Hope this is not too misplaced here, have what is probably a pretty simple electrical question, hoping you guys can help.

I have a starter unit designed for junior dragsters and it turns the wrong way for model engines, am hoping to find out how (if possible) it can be reversed. Switching the leads at the battery has no effect. It is what appears to be an automotive type starter motor running through a gearbox, and is powered by an 8Ah SLA battery.

Thanks,

Craig.

[Comatose]

Its probably a series wound motor. To reverse it, you'll have to open it up, find where the stator windings connect to the brushes, and reverse that. That should reverse the rotation.

[vintage1]

Even if its shunt wound, that will still work..

Will be one big mother of a motor though..take a LOT of LIPOS to feed it.

[Pheasant]

Thanks guys. Some internet sleuthing has determined that it is a series wound motor and to reverse the direction I need to reverse the polarity to the brushes.

Easier said than done (for me). I took it apart and have not yet figured out what to do, am going to try and find some qualified help. I'm sure an electrical guy could take a look and tell me in two seconds what to swap.

[vintage1]

Thanks guys. Some internet sleuthing has determined that it is a series wound motor and to reverse the direction I need to reverse the polarity to the brushes.

Easier said than done (for me). I took it apart and have not yet figured out what to do, am going to try and find some qualified help. I'm sure an electrical guy could take a look and tell me in two seconds what to swap.

Ther will be somehwere inside it a terminal that goes to one of the brushes, and to the a coil that is wound outside the motor. Another end ofthat coil will go to one of the input terminals.

You need to 'swap' the two ends of that coil..or 'swap' where the brushes go to.

either wioll do.

If you can post photos that would help.

[Pheasant]

Quick picture. Shows two brushes, the opposite pair are the same. The one on top comes from the field winding to the brush, isolated from the steel backplate by a phenolic piece on the backplate. The other goes from the backplate to the brush. Common with it's opposite through the backplate. Hope this helps.

[pmackenzie]

Is it possible to re assemble it with the brush assembly rotated 90 degrees?
It appears to be a 4 pole motor and that should reverse it.
The timing might not end up exactly correct. You might have to fine tune it.
Pat MacKenzie

[vintage1]

Sort of brushed outrunner eh?

I am handing over to Pat...

[Pheasant]

Probably not, due to the way the back cover indexes on the backplate and it carries the through bolts which mount the motor to the gearbox. I'll take a look though.

I have a note in to the people who supplied the assembly and they say they can help, hopefully they have a reverse motor.

Craig.


Is it possible to re assemble it with the brush assembly rotated 90 degrees?
It appears to be a 4 pole motor and that should reverse it.
The timing might not end up exactly correct. You might have to fine tune it.
Pat MacKenzie