Metalwork - Lathe and Mill topics

Friday, 11 August 2023

Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

Just tossin this out there , with no load on the motor you will not get the actual amp reading . Also unless you have a good DC clamp meter most DVM that do amps top out at 10 amps .

I thought there was a guy in this group that had a motor shop ? Does the motor absolutely have to have the right angle gear box or can it be a straight gear reduction motor ?

animal

On 8/11/23 9:02 AM, Bill in OKC too via groups.io wrote:

SWMBO' s power wheelchair lift crapped out the other day. New motor is no longer available since the lift is ancient. Manufacturer of the lift removed any OEM markings. It's a right- angle gear motor, which I'll eventually have some photos and dimensions for. This is the in-and-out motor for a Harmar AL-600 lift that fits in the back of a van. Near as I can remember it was made about 2007 or so.

There is no continuity in the motor, but othinf seems burned. I pulled it apart and fiddled with it, and got continuity back. Hooked it back up to power trying to get a current draw reading and it spun up and rapped out again. No continuity again. Brushes look good.

I have a megger for testing insulation, and an assortment of DVMs and at least one analog voltmeter. Somewhere in the library are a couple of older books on motor testing and repair, but haven't found them yet. Any suggestions for resources? I looked at Grainger & McMaster-Carr, also Amazon & Surplus Center. They have similar gear motors but nothing that looks exactly right. Most are either way too light or way too heavy. This is a 12vdc motor, could draw as much as 20amps, but probably closer to 10, and could less. There is another motor on it with a different gearbox. Looks to be about the same motor. May fiddle with that, and get a current draw.

Found one of these motors for sale on the knoppix site for $600, was $400 from Harmar at one time. Seems a bit fishy to me, and can't afford it anyway.

Gotta get ready to take SWMBO to get fitted for a new CPAP mask, and for both of us to get new CPAP machines. Hope someone can point me in a useful direction. Used to be a bunch of folks whe rebuilt motors & alternators/generators around here. Called one and they don't do DC motors at all, and don't think there's anyone left who does.,

Any help will be appreciated!

Bill in OKC

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Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

Found a new place I can get brushes the other day, so put new brushes in the tool post grinder, and got the new power cable for it built, but been distracted ever since. Once I get home from this extended CF of a trip, I'll make a run with the old brushes to Evans Hardware. Ace here no longer carries brushes.

Lift has been in storage since her back got fixed and pulled her out of the power chair a bunch of years ago. Just put it back in service in December. Wouldn't be at all hard for it to have corroded the braid or spring or both. Stretching them to get them out, and putting them back in could have gotten me enough contact to spin it. Will check the brushes in the other motor too.

Thanks, Jon!

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:

Good judgement comes from experience. Experience comes from bad judgement.

SEMPER GUMBY!

Improvise, Adapt, and Overcome.
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The only reason I know anything is because I've done it wrong enough times to START to know better.

Expect in one hand, expectorate in the other. See which one gets full first.

On Friday, August 11, 2023 at 12:44:18 PM CDT, Jon Elson <elson@pico-systems.com> wrote:

On 8/11/23 11:02, Bill in OKC too via groups.io wrote:

SWMBO' s power wheelchair lift crapped out the other day.
New motor is no longer available since the lift is
ancient. Manufacturer of the lift removed any OEM
markings. It's a right- angle gear motor, which I'll
eventually have some photos and dimensions for. This is
the in-and-out motor for a Harmar AL-600 lift that fits in
the back of a van. Near as I can remember it was made
about 2007 or so.

There is no continuity in the motor, but othinf seems
burned. I pulled it apart and fiddled with it, and got
continuity back. Hooked it back up to power trying to get
a current draw reading and it spun up and rapped out
again. No continuity again. Brushes look good.

Well, two possibilities. One is the brush springs are shot
and don't hold the brushes against the commutator. On a lot
of motors, if the copper braid that is supposed to carry the
current gets corroded, then the current goes through the
spring, that fries the temper.

This is fixable. Amazingly, it has screw-in brush caps!

Another possible situation is there is an open winding in
the armature. You can check for this by applying a very low
voltage, like maybe a single D cell to the motor, and see if
it pulses and pauses. That is not really easy to fix.

That looks like a REALLY standard motor, but likely it has a
special shaft end with the worm machined into it.

Jon

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Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

Might also be an internal thermal protection switch.

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Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

On 8/11/23 11:02, Bill in OKC too via groups.io wrote:

SWMBO' s power wheelchair lift crapped out the other day.
New motor is no longer available since the lift is
ancient. Manufacturer of the lift removed any OEM
markings. It's a right- angle gear motor, which I'll
eventually have some photos and dimensions for. This is
the in-and-out motor for a Harmar AL-600 lift that fits in
the back of a van. Near as I can remember it was made
about 2007 or so.

There is no continuity in the motor, but othinf seems
burned. I pulled it apart and fiddled with it, and got
continuity back. Hooked it back up to power trying to get
a current draw reading and it spun up and rapped out
again. No continuity again. Brushes look good.

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Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

Bill

this shop is a premier motor rewinder. They are not near you, but you can UPS your unit to them. I have used them in the past and my machinist club also recommends them highly.

im's Electric Motor - Call For A Free Estimate!

4.4(23) · Electric motor repair shop

Lorton, VA · (703) 550-8624

Open ⋅ Closes 5 PM

Regarding the CPAP, all new machines are auto-set for pressure. You don't need fitting like in the dark ages of years ago. You just buy it and run with it and the machine will make sure you have the right pressure all the time through their feedback sensor. Had to go through this with my mom before she passed away and I remember how impressed I was when compared to her first machine.

This unit is the industry leader and if your insurance covers it, it will only cost you the deductible and you can have a new one every 5 years: https://www.resmed.com/en-us/sleep-apnea/cpap-parts-support/sleep-apnea-full-products-list/cpap-machines/airsense-11/

AirSense 11

The ResMed AirSense™ 11 CPAP machine is designed to make starting sleep apnea therapy, and sticking with it, easier than ever before.

www.resmed.com

From: atlas-craftsman@groups.io <atlas-craftsman@groups.io> on behalf of Bill in OKC too via groups.io <wmrmeyers=yahoo.com@groups.io>
Sent: Friday, August 11, 2023 12:02 PM
To: atlas-craftsman@groups.io <atlas-craftsman@groups.io>
Subject: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

SWMBO' s power wheelchair lift crapped out the other day. New motor is no longer available since the lift is ancient. Manufacturer of the lift removed any OEM markings. It's a right- angle gear motor, which I'll eventually have some photos and dimensions for. This is the in-and-out motor for a Harmar AL-600 lift that fits in the back of a van. Near as I can remember it was made about 2007 or so.

There is no continuity in the motor, but othinf seems burned. I pulled it apart and fiddled with it, and got continuity back. Hooked it back up to power trying to get a current draw reading and it spun up and rapped out again. No continuity again. Brushes look good.

I have a megger for testing insulation, and an assortment of DVMs and at least one analog voltmeter. Somewhere in the library are a couple of older books on motor testing and repair, but haven't found them yet. Any suggestions for resources? I looked at Grainger & McMaster-Carr, also Amazon & Surplus Center. They have similar gear motors but nothing that looks exactly right. Most are either way too light or way too heavy. This is a 12vdc motor, could draw as much as 20amps, but probably closer to 10, and could less. There is another motor on it with a different gearbox. Looks to be about the same motor. May fiddle with that, and get a current draw.

Found one of these motors for sale on the knoppix site for $600, was $400 from Harmar at one time. Seems a bit fishy to me, and can't afford it anyway.

Gotta get ready to take SWMBO to get fitted for a new CPAP mask, and for both of us to get new CPAP machines. Hope someone can point me in a useful direction. Used to be a bunch of folks whe rebuilt motors & alternators/generators around here. Called one and they don't do DC motors at all, and don't think there's anyone left who does.,

Any help will be appreciated!

Bill in OKC

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Re: [atlas-craftsman IO] OT-how to test and repair DC brushed motors.

On Fri, Aug 11, 2023 at 11:02 AM, Bill in OKC too wrote:

Harmar AL-600

ebay has a couple of motors listed: https://www.ebay.com/sch/i.html?_nkw=harmar%20al%20600&norover=1&mkevt=1&mkrid=711-34002-13078-0&mkcid=2&mkscid=102&keyword=harmar%20al%20600&crlp=_&MT_ID=&geo_id=&rlsatarget=kwd-76897272266827:loc-190&adpos=&device=c&mktype=&loc=44051&poi=4080&abcId=&cmpgn=395417210&sitelnk=&adgroupid=1230353719090437&network=o&matchtype=e&msclkid=4c4e497ee5ca155df2b12da8871fdd25

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[atlas-craftsman IO] OT-how to test and repair DC brushed motors.

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