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View Full Version : OT - DC PM motor source??



alanganes
08-14-2010, 10:14 PM
Hi all,
Just wondering if any of you guys has any leads on where I might find a permanent magnet DC motor like this one:
http://img.photobucket.com/albums/v479/alanganes/HSM_Board/IMG_0269.jpg

It is 12VDC, the case is ~3" in diameter and ~5" long. Shaft is 0.375" dia.
Two brushes. Operation is intermittent.

I do not know the speed, but presume it is fairly high, as it runs into a very large reduction ratio setup to develop lots of torque at low speed. It is used on one of those small trailer mounted cherry picker type boom lifts to rotate the boom. It is similar to this unit but older and much smaller:
http://img.photobucket.com/albums/v479/alanganes/HSM_Board/img-8.png

Next week I will be looking into having this one rewound, and am also trying to track down a factory replacement part, though there seems to be some question as to whether or not parts for this unit are still available. So I am trying to hedge my bets by looking for replacements from other sources.

Any favorite sources for stuff like this?
Thanks!

MaxHeadRoom
08-14-2010, 10:23 PM
You could try Cleveland Motor Controls
http://clevelandmotioncontrol.com/downloads/servo_motors/Brush_Product_Guide.pdf
Typically they make servo motors, I am not sure if they go down to 12v, might be worth a shot.
Or a motor off a 12v bumper winch should do the trick.
Max.

lugnut
08-14-2010, 10:36 PM
Take a look and Burden Surplus Center http://www.surpluscenter.com/prodIndex.asp?UID=2007032412112218 The have all kinds of that sort of stuff.

J Tiers
08-14-2010, 11:38 PM
Looks very 'automotive", but not "recent" automotive (post china syndrome). late 80's early 90's maybe.

Replacement motors of similar type may be available. I have one almost identical running an exhaust fan in the shed....which runs on 12VDC other than the 2500W inverter. I think it was a blower fan motor for the heater blower in some vehicle.

Rich Carlstedt
08-15-2010, 01:05 AM
Try this

http://www.4qd.co.uk/

I have a couple of their units
They have a USA distributor

daved20319
08-15-2010, 01:25 AM
A little off the wall, but you might find something here: http://www.robotcombat.com/store.html No, I don't build battle bots, but I have bought a couple of small motors from them for odd projects. Hope it helps.

Dave

darryl
08-15-2010, 04:34 AM
A water pump motor for a motorhome is about that size. Some years of fords had a pretty beefy windshield wiper motor in that range. My cheapo winch has a similar motor, and some made for retrofit electric bicycles were about that large.

In very general terms, low voltage ferrite magnet dc motors have a power rating roughly equivalent to the size, depending on the duty cycle and rpm rating. Another possible source to consider is electric trolling motors, and another one is camper jacks-

alanganes
08-15-2010, 07:29 AM
I agree Jerry on the "automotive" look to it, that was my thought as well. It has a year 2000 date written on the bottom with a paint marker, so I presume that was the last time it was replaced. I can't seem to pin down a likely candidate for a replacement yet.

I did check all of my first go-to places for this sort of stuff, Surplus center, C&C sales, Herbach & Rademan, Fair Radio, and such as well as a general google and ebay search.
I checked the electric bike and scooter places, those are mostly 24V not much 12V stuff.

I'm sort of amazed that something like this is not a bit easier to find, really. It seems I've seen motors like this a million times and at a glance I figured it would be no sweat to pick one up someplace. I sort of assumed that a few minutes of quality time with Google and I'd just be clicking "Buy it now"(!) and be done.

There is a pretty well appointed automotive electrical place nearby, I plan to stop by there tomorrow on my way home from work. They do rewinding and such there as well, so that is always an option. The armature windings are toast, as are the brushes.

Thanks for taking a look and any other thoughts.

Weston Bye
08-15-2010, 07:40 AM
Does the motor have to be an exact bolt-for-bolt replacement? How does it interface for mounting and connecting to the load? If the exact replacement is not available, you may have to settle for similar rpm and torque and build an adaptor.

Check W.W.Grainger. They carry a lot of replacement motors. You might even find one at McMaster-Carr.

alanganes
08-15-2010, 08:16 AM
Does the motor have to be an exact bolt-for-bolt replacement? How does it interface for mounting and connecting to the load? If the exact replacement is not available, you may have to settle for similar rpm and torque and build an adaptor.

Check W.W.Grainger. They carry a lot of replacement motors. You might even find one at McMaster-Carr.


Good point, Wes. I neglected to mention that the mount is about as non critical as it can be. The motor sits in a vee shaped thing and is held in place with two hose clamps, and drives the load with a v-belt. There is some room around it, so I have some leeway on the overall dimensions as well. I checked Grainger, but did not see anything that looked very close.
Thanks!

MaxHeadRoom
08-15-2010, 10:39 AM
Some of these 12v winches are over 1.5hp and a bit >$60.00 for the whole thing.
http://www.nextag.com/12-volt-winch/products-html
You might even be able to use the gearbox as well.
Max.

kbertoson
08-15-2010, 12:17 PM
Seat position motor. Check a local Pull-A-Part. Looks like it may be close to late 1980's early 1990's Oldsmobile, Buick and Cad. Buy the whole seat. There are 2 or 3 motors on the frame.

darryl
08-15-2010, 02:23 PM
Window motors and seat position motors are fairly powerful for their size, but I wouldn't expect them to run continuously without overheating. I would have to say they are not really suitable because the duty cycle is too low.

I checked through the winches on that site, and a couple of them will have a comparable motor in them. One is 30 bucks, another is 60 bucks. You do have to be careful though because most of those are wound field types and draw a lot of current, so I'd have to say they are not suitable either, at least not as a comparable replacement for the motor you've shown. Yours is a permanent magnet dc motor and should probably not be replaced with a starter type (wound field) motor.

One thing that might make sense though is to use a bit more powerful motor than yours is- and I'm saying that because yours is burnt. It probably was borderline in its application and maybe should have been more powerful to start with.

Weston Bye
08-15-2010, 02:40 PM
Window motors and seat position motors are fairly powerful for their size, but I wouldn't expect them to run continuously without overheating. I would have to say they are not really suitable because the duty cycle is too low. ...

Indeed, most seat and window regulator motors have to be designed to endure an indefinite period of stalled condition. (Stupid drivers, small children, pets standing on the control switch, etc.)

Years ago I built a multitude of test controllers for excersizing test parts in a couple of GM test labs.

Many of the motors are equipped with PTC resistors in series with the motor. When the motor stalls and the current rises, the resistor heats up and its resistance increases, reducing current through the motor to an endurable level. Other motors have a simple thermal switch that opens, cutting off power to the motor until the motor (and thermal switch) cools down.

alanganes
08-15-2010, 09:14 PM
Great idea. I sort of forgot about electric seat motors, those may be just the ticket if I cannot locate something more "original." Thanks for that suggestion!

Weston Bye
08-15-2010, 10:46 PM
Don't jump too fast. Most seat and window regulator* motors are built with an integral worm gear output. The worm is machined directly into the motor shaft and engages a (usually) plastic worm wheel. Also, the business end of the motor shaft is supported by the worm gear housing rather than an end bell on that end of the motor.

*in the industry, a window regulator is the whole mechanism that raises and lowers the window - either motor driven or hand cranked.