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Discussion Starter #1
Does someone know where i can buy brushes to my Prestolite MTY4001 forklift motor?
 

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Discussion Starter #3 (Edited)
Please provide dimensions, quantity (used in motor and that you want to buy), and any markings on the existing brush. Photos of the brushes, holders and comm will help.

https://trupar.com/p/hyster-forklift-motor-brush-single-0289345

Something like this? Not sure about this one. Need info from you and also from seller.

major
Hey Major, :)

I got these,

Do you need some meassurements also?

Dont these look worn? Will i feel an increase in speed and torque if changed?
 

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Hey Major, :)

I got these,

Do you need some meassurements also?

Dont these look worn? Will i feel an increase in speed and torque if changed?
Hi Pota,

No, those brushes don't look worn to the point of needing replacement. And new brushes will not give you increase in speed and torque.

The pictures indicate to me abuse. Repeated overload and arcing without normal (within rated) running time to re-establish proper commutator film and brush face seating. Proper comm surface should show a uniform dark gray patina and brush face a smooth shiny surface.

If you are the one responsible for the abuse, you need to examine the application or lower your expectations regarding motor durability and service life.

Regards,

major
 

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Discussion Starter #5
Hey Major,


I got these,

Do you need some meassurements also?

Dont these look worn? Will i feel an increase in speed and torque if changed?
Hi Pota,

No, those brushes don't look worn to the point of needing replacement. And new brushes will not give you increase in speed and torque.

The pictures indicate to me abuse. Repeated overload and arcing without normal (within rated) running time to re-establish proper commutator film and brush face seating. Proper comm surface should show a uniform dark gray patina and brush face a smooth shiny surface.

If you are the one responsible for the abuse, you need to examine the application or lower your expectations regarding motor durability and service life.

Regards,

major
Hey,

No i havent used the motor. What should i do? Could i use a 600-1000 sandpaper and spin the commutator to repolish the surface? Then connect the brushes and let them run on 12v for a period of 24hour?
 

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Hey,

No i havent used the motor. What should i do? Could i use a 600-1000 sandpaper and spin the commutator to repolish the surface? Then connect the brushes and let them run on 12v for a period of 24hour?
First off, try this. Reassemble the motor. Clamp to bench. At 12 VDC, run for 30 or 40 hours. The current even at no load will be high enough you'll need a large truck charger with good size battery floated across it. Use a fan to keep motor cool.

Take some close-ups of comm surface and brush face. Post them.

If that isn't helping, next try a dressing stone. Then using abrasive cloth. Lastly have it turned and undercut. In the meantime, research commutator/brush care and service on the web or library.

major
 

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Discussion Starter #7 (Edited)
Hey,

No i havent used the motor. What should i do? Could i use a 600-1000 sandpaper and spin the commutator to repolish the surface? Then connect the brushes and let them run on 12v for a period of 24hour?
First off, try this. Reassemble the motor. Clamp to bench. At 12 VDC, run for 30 or 40 hours. The current even at no load will be high enough you'll need a large truck charger with good size battery floated across it. Use a fan to keep motor cool.

Take some close-ups of comm surface and brush face. Post them.

If that isn't helping, next try a dressing stone. Then using abrasive cloth. Lastly have it turned and undercut. In the meantime, research commutator/brush care and service on the web or library.

major
Cool. Ill give it a try. Will a better resurfaced com give more power?

And btw Major. Regarding the rotation of the motor when on. If you look at the picture.
I spun the motor counter clockwise of the brush on the picture. Is that wrong? Or should it go clockwise?
Im asking this because the brush has a special shape, (like a \ where it touches the com ) so i was wondring what rotation it has been doing to form that shape, i guess its been formed like that after years of service 🙂
 

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Cool. Ill give it a try. Will a better resurfaced com give more power?

And btw Major. Regarding the rotation of the motor when on. If you look at the picture.
I spun the motor counter clockwise of the brush on the picture. Is that wrong? Or should it go clockwise?
Im asking this because the brush has a special shape, (like a \ where it touches the com ) so i was wondring what rotation it has been doing to form that shape, i guess its been formed like that after years of service 🙂
Little to no affect w/r/t power.

The brush is designed with the curved surface and comes that way new from the brush vendor. It is purposely angled and suitable for either rotation direction.

major
 

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Discussion Starter #9 (Edited)
Little to no affect w/r/t power.

The brush is designed with the curved surface and comes that way new from the brush vendor. It is purposely angled and suitable for either rotation direction.

major
Good :)

When time comes, do I buy the brushes you posted? Was that the correct one?

Are there other things i can do to the motor to make it fresh and clean so it makes more power like a new one?
 

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Good :)

When time comes, do I buy the brushes you posted? Was that the correct one?

Are there other things i can do to the motor to make it fresh and clean so it makes more power like a new one?
Most EV converters never wear out a set of brushes. And old motors make just as much power as new motors.

major
 
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