Puma 40 pulling to the right.

[rover220]

They gave me some advice about getting brushes that can fit.

...care to share?

As soon as I know I will post.

LIL, here, but don't overlook a mechanical issue-a bent caster wheel fork, for example, will draw a chair one way or the other. I'm not familiar with that particular chair, but have seen bent, cracked or broken frames also lead to tracking issues.

Thanks but it none of them. I have 4 speed levels and is doesn't via off till it's the fastest mode(4)
If I slow down to 3 it's ok.

you have the necessary tools to add in some veer compensation to help with the issue until you sort it.

[terry2]

you have the necessary tools to add in some veer compensation to help with the issue until you sort it.

I've seen that in the program but how to do it is beyond me.
But if the right hand motor is weaker then the left, wouldn't using "some veer compensation" slow it down to what the bad motor can do?

I'm still waiting for someone to take the motors off. Hopefully it will be next week

I'm busy building a new big 3D printer from scratch. Now that I know about

[Burgerman]

I've seen that in the program but how to do it is beyond me.
But if the right hand motor is weaker then the left, wouldn't using "some veer compensation" slow it down to what the bad motor can do?

Yes. Obviously you cant make a faulty motor go faster so it will slow the faster one. But if there's some mechanical/electrical issue causing a veer problem there's only 3 answers.

1. fix it.
2. you have 2 different motors... So still fix it!
2. disguise it via programming...

Personally I would fix it. Or at least find it.

[terry2]

I've seen that in the program but how to do it is beyond me.
But if the right hand motor is weaker then the left, wouldn't using "some veer compensation" slow it down to what the bad motor can do?

Yes. Obviously you cant make a faulty motor go faster so it will slow the faster one. But if there's some mechanical/electrical issue causing a veer problem there's only 3 answers.

1. fix it.
2. you have 2 different motors... So still fix it!
2. disguise it via programming...

Personally I would fix it. Or at least find it.

Fix it is the only way. Thanks again. Sorry about the crap pictures. The writing says

CNHU
108340 R21
HI J270
The I in HI could be a L. Off to search for them :

[terry2]

https://www.amazon.co.uk/dp/B00JNWD0B2/ ... 010919BRDX

That is very close to the size of mine.

[Burgerman]

If the spring/top part is correct, and length OK, then you can very carefully, use a medium fine alum oxide paper (stuck to a flat surface like a bench or glass sheet), reduce the cross section if needed. From say 8mm to 7 or whatever you need. Reduce by enough to allow free sliding movement, no excessive free play, by trial and error.

[terry2]

If the spring/top part is correct, and length OK, then you can very carefully, use a medium fine alum oxide paper (stuck to a flat surface like a bench or glass sheet), reduce the cross section if needed. From say 8mm to 7 or whatever you need. Reduce by enough to allow free sliding movement, no excessive free play, by trial and error.

Thanks for that tip

Now this site that has the brushes http://www.nithsdale-wheelchairs.com/pr ... nits-.html
They have the same number. The ones on amazon are 7mm not 8mm and 11mm not 12mm hmmmm thoughts?

[Burgerman]

My thoughts are that you are relying on a retard with a plastic desk ruler.

Instead of:


Reality is that its maybe 6.553 mm or whatever.

[terry2]

My thoughts are that you are relying on a retard with a plastic desk ruler.

Instead of:


Reality is that its maybe 6.553 mm or whatever.

I've got one of those

I'm going by the site before I guy. But is 1mm smaller in width and depth going to make any difference? I.E 7 x 11mm instead of 8 x 12mm

[rover220]

Means it could move around and wear prematurely.

[terry2]

Update.

A friend who buys stuff from china got me 4 brushes the same size as the amazon link.

They was fitted and worked but still the right motor is weaker. So it looks to me I will need two motors soon.Will use them till they die.

In the mean time I am keeping myself busy wiring up my new home made 3D printer

[Burgerman]

Are you sure its actually weaker? Or caused by

Your joystick position
Different gearing (mismatched incorrect motor has been fitted)
Caster wheel problem
You are testing on a slope...
Etc.

[terry2]

Are you sure its actually weaker? Or caused by

Your joystick position
Different gearing (mismatched incorrect motor has been fitted)
Caster wheel problem
You are testing on a slope...
Etc.

The 4 pole motors came with the chair so I have no idea about them being mismatched.
Casters are A OK.
It didn't o it before.

I tried it out on a very flat piece of road. If I make a long turn to the right it go full speed. If I make a long turn to the left it slows down.
It pulls to the right if i am going straight. I've even reloaded the software that it came with(I saved it out before messing) so know it's not that.

Do you think taking the controller apart and give it a clean could help?

thanks again.

[Burgerman]

Yes. Ideally a wire brush, and some battery acid, and rinse well.


No, don't do that!

[terry2]

Yes. Ideally a wire brush, and some battery acid, and rinse well.


No, don't do that!

I will leave the joystick\controller alone them

[woodygb]

Is there a "Steer Correct" setting in software for your controller ?

[Burgerman]

Lift it up. Stick a DC current clamp meter over 1 motor wire, and see at what Amps it begins to rotate. And the same at max speed. And get a stopwatch and at full speed, count wheel revolutions for exactly 15 or 30 secs. (add a line of tape so you can see it).

Compare:
Left starting Amps
Right starting Amps these should be within 15%.

Same for full speed.
RPM should also be within around 5%

Be sure joystick is in the exact 12 o clock position. And do tests 10 times and average the results...

Post here.

[terry2]

Is there a "Steer Correct" setting in software for your controller ?

I will have a look but I don't remember seeing it in the wizard software.

[terry2]

Lift it up. Stick a DC current clamp meter over 1 motor wire, and see at what Amps it begins to rotate. And the same at max speed. And get a stopwatch and at full speed, count wheel revolutions for exactly 15 or 30 secs. (add a line of tape so you can see it).

Compare:
Left starting Amps
Right starting Amps these should be within 15%.

Same for full speed.
RPM should also be within around 5%

Be sure joystick is in the exact 12 o clock position. And do tests 10 times and average the results...

Post here.

Send me over the clamp meter and I will try it

[terry2]

woodygb wrote:
Is there a "Steer Correct" setting in software for your controller ?

If you mean to off set one motor then yes that is there.

But as it's only been happening lately I would like to try to find out why.

I couldn't edit my other post as the time limit was up to do so.

[woodygb]

Is there a joystick calibration routine? ...as it's possible that your joysticks output has drifted on one side rather than your motor getting weak.

[terry2]

Is there a joystick calibration routine? ...as it's possible that your joysticks output has drifted on one side rather than your motor getting weak.

I will look and try that now and report back.

Thank you

[terry2]

There is a calibration plugin but it needs the rear wheels off the ground. I will get someone to do it for me

Well done woody

[Burgerman]

Its unlikely to be the problem though. Because its hall effect. And if it was far enough out going forwards where the turn is still zero, it would give an error on start up, or rotate on the spot at the zero position.

So... http://www.ebay.co.uk/itm/UNI-T-UT203-D ... Sw0UdXsur- cheapest known brand dc current clamp, WILL find the problem!

[terry2]

Its unlikely to be the problem though. Because its hall effect. And if it was far enough out going forwards where the turn is still zero, it would give an error on start up, or rotate on the spot at the zero position.

So... http://www.ebay.co.uk/itm/UNI-T-UT203-D ... Sw0UdXsur- cheapest known brand dc current clamp, WILL find the problem!

Thanks BM but I wouldn't know aht I'm doing

My mate just tried left it off the ground via the battery box but it lifted up

so he is going to look for another way. I know the mobility shop had a special lift for my chair.

[Burgerman]

tip it on its back.

[Burgerman]

Thanks BM but I wouldn't know aht I'm doing

Turn on. Zero it by pushing 1 button. Clamp over 1 motor wire... Then operate chair and see what it reads. At full speed it should be about 5A At starting speed it may reach about the same. If both read the same all healthy. If one reads substantially more there's a motor problem.

[terry2]

tip it on its back.

I'll tell him that but it wights a bout 15 stone! not an easy job.

He just told me the aluminium back seat wouldn't hold the wight. And teher is a electric motor contented for the seat to tilt back.

[B400 user]

bump the front wheels up a kerb or whatever and then lift and place a small block or whatever under the tippers use a wheel caulk as needed to hold it in place. Use imagination as required.

[terry2]

UPDATE.

I've solved 80% of the problem. The person who had it before me had the wrong controller programed flashed.
I used a backup file from a guy who has the right option for my controller. Very little pulling to either side now.

I've left the cheap Chinese brushes in to see how long they last. Thank you to all that helped