Wheelchair motor heating up -- troubleshooting

[ouichaise]

TL;DR Summary

what the prob . what can i do my self

hi i have a 646 se from quickie powerwheel chair pride company.i bought it used

it always have had a pull on the right side as if the right side motor was weaker so to go strait i had to aim a bit at the left with the joystick.This summer the right motor or close to it started making a sound.recently i had the tire changed we took a brush from the right motor and it was close to the line quite used but still coupe mm to reach the line on it.
last week i opened the joystick and glued something ( i hope i did not mess anything up.)
today i asked the motor to go fast(i was in a hurry max speed) and it smelled smoke like burned varnish. i stopped the motor it was very hot.saw 2 smoke vaps go out. waited 10 minutes, from there on the chair was pulling a LOT on the right side almost not working. was it a protection device? Called a taxi to stop rolling with it while hotwhy did the motor heated up so much more than the left one( i was used to using it high speed befor and never had prob)What to do now? what does it look like?should i look to buy a new used motor or even used wheelchair change the brushes ? what to do thxcould it be bearing? Listen to the sound the right motor it makes video belowvideo with soundpicture of motor and chair

[/URL]

mp3 only sound[Moderator's note: links to external, french provider removed.]

 

[sysprog]

smelled smoke like burned varnish. i stopped the motor it was very hot.saw 2 smoke vaps go out

Safety First call for aid.

 

[Tom.G]

The two most likely are the brake not releasing or the motor has an internal short in a winding, with the brake being the most likely. Many motors of that type have the brake built into the motor. In either case, the motor is damaged to some extent, after all, some of the "Magic Smoke" escaped.

By the way, incase you did not get a User manual with the chair, it is available as a PDF file at:
https://www.sunrisemedical.com/getattachment/2583e7b3-15b5-438a-a244-973056d91951/.aspx

If the problem is the brake, it could be the linkage from the brake release handle to the motor; inspect that for any problems.

Unfortunately, a Moderator decided to remove the video/audio link from your post so I can not hear it.

You can send the video/audio links to me by mousing to my name at the top of this post and clicking on "Start conversation."

Cheers,
Tom

 

[Frodo]

it always have had a pull on the right side as if the right side motor was weaker so to go strait i had to aim a bit at the left with the joystick.

That sounds like the brake is sticking on. Freeing the brake may be enough to allow it to continue operating assuming the brake has not been damaged so much as to make it unreliable in future. The brake prevents a stationary chair from moving so you are at considerable risk when using the wheelchair on a slope. A parked wheelchair may move.

it smelled smoke like burned varnish.

That smells of serious problems with the motor as the windings seem to have overheated. It could be a shorted turn but is more likely to be overheating. A damaged rotor can be rewound by a motor rewind specialist repairer.

My advice: Take it to a wheelchair service centre for it to be checked and repaired. It could fail completely or the motor even catch fire at any time.

Quickie wheelchairs website is https://www.quickie-wheelchairs.com/ where, in the US, a new Quickie S-646 SE Rear Wheel Power Wheelchair is $8,495.

Full details on the motor including an exploded diagram can be found here where a new motor is less than $1,000. A new motor, if required, seems a worthwhile repair.

EDIT: The User Manual says there is a electromagnetic brake.

While the exploded diagram does not show a brake anywhere closer inspection of the motor shows there appear to be four pins on the plug suggesting the brake is internal in the motor(s).

The motor probably drives via a worm wheel on its shaft (it also provides the 90 degree change of direction needed).

 

[Frodo]

And some more thoughts ...

1 The manual says there is a brake. It or something else is probably binding. Check what. Is greasing required?

2 It is always worth checking the brushes on a DC motor.

 

[Frodo]

Yet another thought.

See this forum post One of my wheelchair motors overheats and stops working which links to this video Electric Wheelchair Motor Test & Brake Removal by VOG (VegOilGuy)

youtube has several videos - eg see

- inside a wheelchair motor (VLOG 333), and
- diagnose and repair wheelchair scooter motor brake gearbox fault problem 1800 717 1252

The motors may not be identical to yours but it should help.

Incidentally you can generally hear when an electromagnetic brake is engaged or disengaged. It is much louder than a click - more like a bang or clonk. When coming ON it acts very rapidly and the wheelchair may jerk to a halt.

 

[ouichaise]

tom G - hi. may be the smoke came from a non wire part. if i fix the heat issue will i still be able to use it ? what do you mean by will be broken?

-eng is my second language : what do you mean by the linkage from the brake release handle to the motor
do you mean the sort of round ball i pull do put the motor in neutral position (disengaged gear i imagine ) to allow someone to pull the chair for example?

 

[ouichaise]

That sounds like the brake is sticking on. Freeing the brake may be enough to allow it to continue operating assuming the brake has not been damaged so much as to make it unreliable in future. The brake prevents a stationary chair from moving so you are at considerable risk when using the wheelchair on a slope. A parked wheelchair may move.That smells of serious problems with the motor as the windings seem to have overheated. It could be a shorted turn but is more likely to be overheating. A damaged rotor can be rewound by a motor rewind specialist repairer.

My advice: Take it to a wheelchair service centre for it to be checked and repaired. It could fail completely or the motor even catch fire at any time.

Quickie wheelchairs website is https://www.quickie-wheelchairs.com/ where, in the US, a new Quickie S-646 SE Rear Wheel Power Wheelchair is $8,495.

Full details on the motor including an exploded diagram can be found here where a new motor is less than $1,000. A new motor, if required, seems a worthwhile repair.

EDIT: The User Manual says there is a electromagnetic brake.

While the exploded diagram does not show a brake anywhere closer inspection of the motor shows there appear to be four pins on the plug suggesting the brake is internal in the motor(s).

View attachment 275822

The motor probably drives via a worm wheel on its shaft (it also provides the 90 degree change of direction needed).

hi i don't have that kind of money. no job no insurance. yes i believe it is electromagnetic the kind of brake at the end of the motor.

 

[ouichaise]

when i last went to the repair the guy took a brush out to look at it and place it back.

Could too used brushes(4 per motor) or misplaced bruches be source of heating and pulling and that sound where mp3. those are legit

 

[ouichaise]

And some more thoughts ...

1 The manual says there is a brake. It or something else is probably binding. Check what. Is greasing required?
if it is the brake that is partially touching, how to solve that?

2 It is always worth checking the brushes on a DC motor.

whAT DO i need to check exactly? color? form ?

 

[Tom.G]

what do you mean by the linkage from the brake release handle to the motor
do you mean the sort of round ball i pull do put the motor in neutral position (disengaged gear i imagine ) to allow someone to pull the chair for example?

Yes, that is what I mean.

may be the smoke came from a non wire part. if i fix the heat issue will i still be able to use it ?

Probably not. The only way I can think you could do that is if most of the heat was coming from the brake. You said you smelled hot varnish from the smoke. As far as I know there is little varnish in the brake. The wire windings in the motor are coated with varnish for electrical insulation. When that varnish insulation fails the different turns and layers of wire in the motor connect to each other. This causes more current to flow thru the motor and also make the motor less powerful.

From the audio file you sent me, there are definite mechanical problems. To me it sounds like it may be a damaged bearing, damaged gearbox, or damaged brake -- or any combination of them. Finding repair parts would be very hard to do... first you need to take apart the motor, brake, and gear box to find what is needed; find new parts; and put it all back together so it works

I am sure the motor needs to be replaced. It might work for a short time if all other problems are fixed, but it is sure to fail completely very soon.@Frodo supplied a nice exploded view of the motor area in post #4 above. The manual brake release is at the lower left of the view, it is the handle on the left end of the motor. The multiple-disc brake would be in the motor housing to the right of that handle and before the brushes.

The brake is spring loaded to hold the brake engaged. The handle compresses the spring, releasing the brake. The brake is also magnetically operated. There are two ways this can be done. Either the brake coil is in series with the motor so when current flows thru the motor it releases the brake, or there may be a separate wire from the Controller circuit board to release the brake.

A possible reason for the troubles could be the Controller circuit board failed and was not releasing the brake (putting it in neutral, as you called it) when running. This could have caused the other problems.

@Frodo also had a good idea about having the motor rewound if that fits the conditions. Much lower cost than a new motor!

At this point, I see a few possible ways to fix this:
1) Have it repaired by someone that sells that brand of chair. Most expensive and most reliable. At least here in the US, they often have chairs available for rent or to loan during repairs.
2) Have it repaired by an independent shop that normally repairs chairs and is familiar with them. Not as expensive as #1 and not as reliable, they likely won't get servicing information from the manufacturer and may have trouble getting parts.
3) Find someone with mechanical and electrical ability to work on it. Maybe cheaper but not at all reliable. It will probably take longer, and if they can not fix it or do a poor job it is very hard to get your money back... and you have lost much time.
4) Do it yourself. If you choose this, replace the motor and gearbox and any wheel bearings. And hope there is nothing else wrong, like the Controller circuit board. This will also likely take the most time unless you can easily find a motor and gearbox.

If you choose to do it yourself, consider buying new, not used, parts... unless you can get around without the chair if the used parts do not work.

Oh, just as a point of information, the gear box is almost certainly bevel gears. Worm gears typically can not be back-driven. I once helped a chair user when their battery died while crossing a 6-lane street. At that time I did not know about the manual break release/disengagement. A few others gathered to help also. We would push the chair about 10 feet and it would suddenly run for 2 feet. By pushing it, the motor acted as a generator to recharge the battery. There were a few skinned knees the first time that happened!

EDIT: "Could too used brushes(4 per motor) or misplaced bruches be source of heating and pulling and that sound where mp3. those are legit"

Yes. If a brush is completely worn away that could be an original source of the problem. The trouble is, even if that was the first cause there is much more motor damage now.
/EDIT

Cheers,
Tom

Note: I just looked at the parts list and realized there are six different motor listed. Get the correct one if you choose other than a dealer to do the work. Also check to see if the two motors you have on the chair are mates.

 

[ouichaise]

Yes, that is what I mean.

Probably not. The only way I can think you could do that is if most of the heat was coming from the brake. You said you smelled hot varnish from the smoke. As far as I know there is little varnish in the brake. The wire windings in the motor are coated with varnish for electrical insulation. When that varnish insulation fails the different turns and layers of wire in the motor connect to each other. This causes more current to flow thru the motor and also make the motor less powerful.

From the audio file you sent me, there are definite mechanical problems. To me it sounds like it may be a damaged bearing, damaged gearbox, or damaged brake -- or any combination of them. Finding repair parts would be very hard to do... first you need to take apart the motor, brake, and gear box to find what is needed; find new parts; and put it all back together so it works

I am sure the motor needs to be replaced. It might work for a short time if all other problems are fixed, but it is sure to fail completely very soon.@Frodo supplied a nice exploded view of the motor area in post #4 above. The manual brake release is at the lower left of the view, it is the handle on the left end of the motor. The multiple-disc brake would be in the motor housing to the right of that handle and before the brushes.

The brake is spring loaded to hold the brake engaged. The handle compresses the spring, releasing the brake. The brake is also magnetically operated. There are two ways this can be done. Either the brake coil is in series with the motor so when current flows thru the motor it releases the brake, or there may be a separate wire from the Controller circuit board to release the brake.

A possible reason for the troubles could be the Controller circuit board failed and was not releasing the brake (putting it in neutral, as you called it) when running. This could have caused the other problems.

@Frodo also had a good idea about having the motor rewound if that fits the conditions. Much lower cost than a new motor!

At this point, I see a few possible ways to fix this:
1) Have it repaired by someone that sells that brand of chair. Most expensive and most reliable. At least here in the US, they often have chairs available for rent or to loan during repairs.
2) Have it repaired by an independent shop that normally repairs chairs and is familiar with them. Not as expensive as #1 and not as reliable, they likely won't get servicing information from the manufacturer and may have trouble getting parts.
3) Find someone with mechanical and electrical ability to work on it. Maybe cheaper but not at all reliable. It will probably take longer, and if they can not fix it or do a poor job it is very hard to get your money back... and you have lost much time.
4) Do it yourself. If you choose this, replace the motor and gearbox and any wheel bearings. And hope there is nothing else wrong, like the Controller circuit board. This will also likely take the most time unless you can easily find a motor and gearbox.

If you choose to do it yourself, consider buying new, not used, parts... unless you can get around without the chair if the used parts do not work.

Oh, just as a point of information, the gear box is almost certainly bevel gears. Worm gears typically can not be back-driven. I once helped a chair user when their battery died while crossing a 6-lane street. At that time I did not know about the manual break release/disengagement. A few others gathered to help also. We would push the chair about 10 feet and it would suddenly run for 2 feet. By pushing it, the motor acted as a generator to recharge the battery. There were a few skinned knees the first time that happened!

EDIT: "Could too used brushes(4 per motor) or misplaced bruches be source of heating and pulling and that sound where mp3. those are legit"

Yes. If a brush is completely worn away that could be an original source of the problem. The trouble is, even if that was the first cause there is much more motor damage now.
/EDIT

Cheers,
Tom

Note: I just looked at the parts list and realized there are six different motor listed. Get the correct one if you choose other than a dealer to do the work. Also check to see if the two motors you have on the chair are mates.

HI
the stick is indeed slack but that stick is related to the gearbox , it is disengage or engage, how can that create friction in the motor?

are six different motor listed. G where can you see this list?

is said varnish smell but it was more burned smell really.
So you think i can get a used chair for other model and cie and install its motor and electronic on my present chair?

 

[Frodo]

Either the brake coil is in series with the motor so when current flows thru the motor it releases the brake, or there may be a separate wire from the Controller circuit board to release the brake.

See the youtube video links in post #6 where similar motors are disassembled and the brake removed.

Oh, just as a point of information, the gear box is almost certainly bevel gears.

I am certain you are correct.

With a little more thought I should have realized that there needs to be a way of moving a chair with a flat battery, and disengaging a worm is much more complicated - read expensive - than disengaging a brake. A worm drive would also need strong thrust bearings on the motor shaft to take normal and impact axial loads.

The user manual talks about the brake lever which, as the videos show, disengages the motor brake. The motor exploded diagram shows it at the brake end, with the brake beyond the armature.

By pushing it, the motor acted as a generator to recharge the battery. There were a few skinned knees the first time that happened!

My wife's off-road scooter has a full four quadrant motor controller (made by Curtiss and used in forklift trucks etc) which puts the brake lights on whenever the scooter overruns and it regenerates. It also has a key switch to disengage the brake.

 

[Frodo]

[It is always worth checking the brushes on a DC motor] whAT DO i need to check exactly? color? form?

I am becoming concerned that you do not appear to have the basic knowledge to do this diagnosis or repair in a safe manner. Anyone with even slight knowledge of DC motors should not need to be told how to check brushes.

Working on battery powered wheelchairs is EXTREMELY DANGEROUS unless and until the batteries have been completely disconnected and removed. As an absolute minimum, batteries should be disconnected, and have their terminals insulated and made completely safe so there is absolutely no possibility of the battery(s) being shorted.

Accidentally shorting a wheelchair battery could cause hundreds and hundreds of amps to flow and whatever does the shorting could to be heated to an extremely high temperature or even vaporised, spraying you with molten or vaporised metal and causing a fire.

Please seek the advice of someone skilled who is local to you. Tom.G is giving you excellent advice - follow it.

 

[ouichaise]

yes i listen the the videos and the guy say to reput the unes brush at the exact same position which the repair man did nt seem to care.
I always ask to be presente when the reparation is maid and not every mecanician is as knowlegded as should be so i ask to know if the job is done correctly

 

[ouichaise]

i tried the chair 2d and the 2 motors do the click when starting and stopping.
it did not seem to overheat and it does not drag as when it was hot.
since the lever with the ball was loose i tapped it so it stays in its possition.
after 10 min ride both motor has same temp approx.
So could it be that the slack in the ballarm to engage disengage the transmission could be the cause of all that?

other questions , the brush the guy took out was used but not yet reaching the line . and after the line there is still like 1 cm before getting to the metal. could the sound come from the used brush ? should i just wait that it is used closer to the metal to change it? ( i use it only4 months a year)

 

[Tom.G]

After listening to the audio of your motor again, I realized there is another possibile reason/cause for all the problems. One of the motor brushes could be completely worn down and the spring that pushes the brush may be riding on the commutator (motor rotor). This could explain the large sound difference between Forward and Reverse.

Please check all of the motor brushes. If one is much worse than the others, then probably just a motor replacement is needed. (or a motor repair if time is not critical.)

since the lever with the ball was loose i tapped it so it stays in its possition.
after 10 min ride both motor has same temp approx.
So could it be that the slack in the ballarm to engage disengage the transmission could be the cause of all that?

Yes, it could be. But both the smoke and the smell indicate there is already damage somewhere. (Keep a hammer with you when you go out. ) How do the forward and reverse sounds compare to what they were.

It comes down to how much you want to risk a total failure when far from home, in bad weather, at night.

Only you can decide that. The safest way is to both find and fix the cause, and to repair any damage.

yes i listen the the videos and the guy say to reput the unes brush at the exact same position which the repair man did nt seem to care.

Yes, for best operation the brushes should be put back in the same position. It is usually not a big problem if it is not done. You will have a little less power while the brush wears down a little faster until it is the same shape. It may slightly increase wear on the contacts on the motor rotor (the commutator).

Back in post #10 you asked:

2 It is always worth checking the brushes on a DC motor.

whAT DO i need to check exactly? color? form ?

Things to look at are:
1) Length. Long enough so the spring that pushes them can supply enough force for good contact to the commutator..
2) Cracks.
3) Signs of arcing (sparking). This will usually show as small areas of color change, often a light grey. Minor arcing is normal. A few areas the size of the head of a sewing pin would just say, "I better look again sometime to see if it gets worse."
4) The curved surface should be shiny with no deep grooves. Mild/shallow grooves are common. Deep grooves show the commutator is rough/damaged and should be resurfaced ("turned", machined to remove uneven spots).
5) Oil. There should not be ANY oil on the brushes. If there is, replace them. If the new ones get oil on them, fix the oil leak. This can rapidly damage the motor. The good part is it almost never happens.

Please keep us aware of how the project goes.

Cheers,
Tom

 

[ouichaise]

(Keep a hammer with you when you go out.

hi thanks for re earing hammer what for? or it is a joke?

i have used it 2 days a bit and both seem like same temp.
the brushes i ll go see the guy back for him to check them

y slightly increase wear on the contacts on the motor rotor
- could that have caused the high heat?

If the new ones get oil on them, fix the oil leak. This can rapidly damage the motor
he did spray wd40 on the motor to prevent futur rust, could that be the prob
- why

it is true that it gives me anxiety to risk to be stuck. I was thinking of not going back see the guy(cause sometime i come back with prob i didnt have before lol) and take bigger and bigger distance but your comment on the possibility that one of the 4 is on metal is important.
) Length. Long enough so the spring that pushes them can supply enough force for good contact to the commutator. - this is subjective these pieces are slow to get smaller and if they are all on the line or a bit longer is it ok to leave them like tath and check them next year?
- i i change on brush well the 3 other will be shorter hence less pressure on the commutator. is that a probleme ? id like to know the consequence cause buying 4 instead of 1 is 90 dls instead of 15...

- ill go check the sound and come back

 

[Tom.G]

Hammer:
To keep the handle for the motor brake where it should be.

y slightly increase wear on the contacts on the motor rotor
- could that have caused the high heat?

No! Way too much heat for that.

he did spray wd40 on the motor to prevent futur rust, could that be the prob
- why

On the outside of the motor, not a problem.
Inside the motor is a problem.

- why

1) Because oil on the brushes will cause poor contact with much sparking, causing damage to the commutator.
2) WD40 is not a good lubricant, it is a solvent with a little oil mixed in and is good for cleaning grease out of bearings and other places. It would not be a good lubricant for the motor bearings.

Length. Long enough so the spring that pushes them can supply enough force for good contact to the commutator. - this is subjective these pieces are slow to get smaller and if they are all on the line or a bit longer is it ok to leave them like tath and check them next year?

"On the line or a bit longer... next year" If you use the chair to go across the street once a week, sure. The line shows the brush length that the people that designed the motor decided was the limit for continued reliable use without risking damage. Pay attention to it.

- i i change on brush well the 3 other will be shorter hence less pressure on the commutator. is that a probleme ? id like to know the consequence cause buying 4 instead of 1 is 90 dls instead of 15...

Probably OK from a mechanical and electrical view. The problem is we Humans tend to forget things, and even tell ourselves that "Oh, it is OK"; even when it is not OK.
If the the brushes are worn nearly the same and at or very near the line, then the easiest and most reliable thing is to replace all the brushes in that motor. That way you won't forget to get them checked and can be easy in your thoughts about being stranded if it stops working.
Also if you find that one brush is wearing much more, or less, than the others, you will know there is a problem with that motor.
(Also going to the shop 4 times will likely cost more than changing all 4 at once.)

Cheers,
Tom

 

[ouichaise]

Hammer:
To keep the handle for the motor brake where it should be.

wow that sounds violent , il is loose i don't see how hitting it with force would help.
here is the sound i recorded,
after a medium 15 min ride, the motor on right was hotter than the other but not super hot nor ouch .

im kind of affraid that the guy would not know how to verify the brakes or solve it.

 

[Tom.G]

Attached is the audio file referred to in the above post.
Remove the .txt extension and play as an ordinary .mp3 audio file.

The OP messaged me with the following:
that is the sound it sounds like more beat per minute compared to the other time.

I responded with:

Is that with the motor mounted on the chair and turning the wheel?
If so, how do the Beats compare with the wheel rotation speed?

If easy for you, could you do a video with sound that shows the wheel rotation and the sound. Put a mark on the wheel so it is easy to see the speed. And run the motor fairly slow for two wheel rotations, so I can count the Beats per revolution.

Thanks.