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Electric motors question

imiceman44

imiceman44

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So guys who know old electric motors with brushes, I took one appart when it stopped working figured it needs brushes but turns out the spring pushing on it disintegrated.
I replaced the spring and put it back together.
Now it runs backwards.
I didn't touch the brushes location, it only has 2 brushes, the battery is not even disconnected, just turned of the switch.
How does this happen.
It's a 24v dc by the way on my electric scooter.

20200829_212441.jpg
 
Does it use permanent magnets or a field coil? Are you sure you assembled it exactly the same way (i.e. case that holds the armature is in the same orientation as it was and not out of alignment)? Sorry, can’t view the pic.
 
rampage said:
Does it use permanent magnets or a field coil? Are you sure you assembled it exactly the same way (i.e. case that holds the armature is in the same orientation as it was and not out of alignment)? Sorry, can’t view the pic.
Click to expand...
Permanent magnet.
I didn't unhook any wires, just pulled the brushes from the channel they were in, put a spring and put them back in, sanded the rotor contacts and reassembled.
 
rampage said:
Does it use permanent magnets or a field coil? Are you sure you assembled it exactly the same way (i.e. case that holds the armature is in the same orientation as it was and not out of alignment)? Sorry, can’t view the pic.
Click to expand...
And for the record I am not a new in electric work, that's why I am stumped and asking here.
This shouldn't happen but it is happening
 
The only thing I can think of is, could the the throttle go bad and reverse polarity internally?
It was running fine minutes earlier then quit, realized it was the motor after diagnosis and took it apart
 
rampage said:
Does it use permanent magnets or a field coil? Are you sure you assembled it exactly the same way (i.e. case that holds the armature is in the same orientation as it was and not out of alignment)? Sorry, can’t view the pic.
Click to expand...
Just thought of something, could I have put the housing with the magnets upside down and caused it?
 
There is a go-cart site online that I read ,they showed how to make a car starter motor reversible (the old school type with field coils),and they also showed how to reverse the polarity on a permanent magnet starter to reverse it too..
I bet it is possible to put the magnet casing on "180 off" .flipping it end to end,and that probably would reverse the polarity due the the north & south poles on the magnets now being opposite from the position they were in originally..
A poster on a garden tractor site I frequent "rebuilt" his starter on a Briggs & Stratton and he had that issue,the bendix gear would not pop up and spin the flywheel,he found it it was turning backwards,and he had to take the starter back off and apart and flip the casing with the magnets around.

I guess its important to mark things before taking them apart,I have done stuff like this too many times by not paying attention to how things looked before I unscrewed them!..some things require phots taken,because my brain doesn't always recall every detail..:doah:
 
Blue85 said:
Can't the polarity be reversed?
Click to expand...
Unfortunately it's not that easy, with the controller in the mix, having all the plugs idiot proof so you don't reverse polarity by mistake, I have to take it apart and flip the magnets.
Gotta do it the right way.
Thanks guys for the feedback.
I know usually I always know the answer in the end but if I don't start bouncing ideas out in the open and hearing myself I don't think of everything.
 
Learning lesson: mark things for direction/clocking before disassembling.

Hopfully flipping that fixes it.
 
JoshHefnerX said:
Learning lesson: mark things for direction/clocking before disassembling.

Hopfully flipping that fixes it.
Click to expand...
Normally I lay things out and reverse on assembly.
This time around the little boys came and were messing with everything and they caused me to drop it, and since it looks the same I just picked it up and put it on.
Lesson learned definitely
 
rampage said:
Sure, blame it on the kids. :rotfl:
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Some days I wonder if I made a mistake taking on young kids at my age.
My patience is fading, I am 54 and have a 3yo and a 4yo, both boys.
They are in everything, I can't leave anything in sight and even if I am working on something they are all over me and they want to see what I am doing, from my lap :doah:.
That night they got in my toolbox and dumped my sockets and they rolled down the driveway, and what is worse is they got to scooter that is on a kickstand and they pull on It and it falls on them and they get hurt.
But then I think about it and I wouldn't have it any other way.
:pimp:
 
I’m sure you did the exact same thing to your dad too.
Karma’s a bitch isn’t it. :haha:
Now hurry up and fix it so we know if that’s the issue.
 
imiceman44 said:
Unfortunately it's not that easy, with the controller in the mix, having all the plugs idiot proof so you don't reverse polarity by mistake, I have to take it apart and flip the magnets.
Gotta do it the right way.
Click to expand...
I assumed there was a plug somewhere you could extract the pins and swap them like on most connectors. But not all PM motors work 100% the same in both directions, so overall rebuilding again is better, unless you think it might break.
 
rampage said:
I’m sure you did the exact same thing to your dad too.
Karma’s a bitch isn’t it. :haha:
Now hurry up and fix it so we know if that’s the issue.
Click to expand...
Actually I never did.
It's weird, I tried to do everything like my parents did because they did a great job, but it's not working for me, kids these days are different, they don't give a shit.
 
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