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Using old washing machine motors

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Ian P06/09/2011 20:49:57
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I am considering using an ex Bosch washing motor to drive a small milling machine (Morse 2 spindle). The motor has more than enough power, 300W, but rather more than enough speed at 14,500RPM!
 
I was going to have a 3:1 ratio using a polyvee belt so that the maximum speed will be about 5000 RPM. Mostly I intend to be using small cutters and was hoping to use the original speed controller so that the spindle can be run hopefully as low as a few hundred RPM.
 
The motor is a 'universal' type and has separate connections for the brushes, field, and tacho-generator and these were wired to its original PCB as is a speed control potentiometer, it must have had variable speed spin or some such feature.
 
Does anyone know what sort of torque is going to be available at the lower speeds? I have done quite a bit of searching and whilst there is quite a lot of information on ex w/m motors I cannot find anything pertinent to this particular motor.
 
Ian P
John McNamara07/09/2011 00:50:05
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Hi Ian

Another possibility is exercise treadmill motors. There is a lot info on Google Not an uncommon site on hard rubbish days. Some are around 2kw and you get a speed controller. I am keeping my eye out.

Cheers
John
Ian S C07/09/2011 12:21:19
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The treadmill motors I'v come across are as John says about 2kw, but they are 200v DC permanant magnet motors, and they start working at anything from 12v up, they also make a fine generator. The last one that I had went to a friend to power a water pump, he was running the pump with a generator that was struggling with the starting current of a 1/4hp induction motor. A 220V DC genny handeled it nicely. Ian S C
Ian P07/09/2011 12:27:51
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Good info on the treadmill motors which I will bear in mind. I was going to try the w/m motor I mentioned 'because I already had it'.
 
On reflection that not a very good reason, I've got lots of stuff which I know I will never use so the w/m motor might just join the rest of its friends on the shelf.
 
Ian P
ViKARLL22/09/2011 11:03:51
13 forum posts
Hi Ian P,
 
Firstly, you are lucky to get this Universal Motor from a WM, since most of them produced anything this side of 10 years are equipped with 2 pole induction motors, perhaps due to low production cost.
 
I am not an Electrical Engineer but an ICT Engineer, so from the little bit of basic motor theory my memory can serve, the torque equation has a V squared in it, inversely proportional.
 
Secondly, I have a Universal Motor from an old Hoover VM too, sitting along with the rest of the junk since the days of Adam. I have plans to use this on a mini lathe I intend to build one of these days. My plan is to drop the speed of the motor by 1/2 or so mechanically and the rest by a PWM.
 
BTW, if you look at a wood router for example, which has Triac based speed control, you can’t grumble much about the torque at low speeds I guess.
 
 
ViKARLL

Edited By ViKARLL on 22/09/2011 11:08:01

Les Jones 122/09/2011 17:38:43
2243 forum posts
153 photos
Hi Ian,
Here is a link to a website selling a speed controller for a washing machine motor.
 
If you click on the link to the home pageof this site there is a link to using a washing machine motor to power a power hacksaw. This speed controller uses the TDA1085C IC. Here is a link to the data sheet on this IC so you could build your own speed controller.
 
 
Les.
 
Ian S C23/09/2011 12:58:35
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I rigged up a univesal motor from a Hoover Twin tub with a speed controller and a flexable drive, not entirely succesful, not enough torque, I think a belt drive reduction would get around that. The motor is hung on a rail above my work bench. Ian S C
John Haine23/09/2011 13:22:07
4428 forum posts
264 photos
The motor you have is series wound which is why it runs at such a high speed - you're lucky it didn't smear its commutator over the workshop. These motors need either to be run with a load such as a fan (as in a vacuum cleaner) or a speed controller to limit their maximum speed. There was an article in MEW several years ago on how to use a washing machine speed control module (which I think is available as a spare). Incidentally I doubt if many washing machines have induction motors as they inherently need variable speed which is difficult without an expensive VFD. Certainly our new one (a few months old) and the LG that it replaced used universal motors (which are very cheap to make), as given away by the characteristic commutator whine at higher speeds.
Ompa Ompa23/09/2011 13:52:31
43 forum posts
1 photos
One article, again several years ago, told how a father and son built a bench grinder, using a vacuum cleaner motor. The points raised above about speed proved fatal for the father when he ran the machine. The grindstone wheel apparently exploded and cut his throat as pieces flew through the air, due ostensibly to the safe rpm speed of the grindstone wheel being exceeded.
Motto here is, extreme care should be taken when using these motors out of normal practices'
Ian P23/09/2011 14:57:01
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I have not responded to theis thread since I started it as I have been away but what I did not say originally is that the washing machine was quite old when I disposed of it although it had hardly ever been used. It had a variable (spin?) speed control potentiometer on the front panel so I carefully kept all the wiring intact and left it all connected to the various items and dropped it into a large cardboard box.
 
When I decided to use the motor recently I took it all out of the box and without thinking, unplugged all the bits but stupidly did not make a diagram! Some connections are correct (multipin plugs etc) but the speed control PCB has a row of terminals that are unidentified. The controller module is of Italian manufacture but I have been unable to find any details online. There are similar motors/controllers shown in several YouTube clips but not enough details given to safely wire this one up. I could make a totally new controller from scratch but if I could get the original to work it would save a lot of messing about.
 
Because the motor is well made, a decent size and has tacho feedback I was hoping that it would have reasonable torque at lowish revs but in spite of me having quite a good electronic knowledge I have not been able to run it to test.
 
Ian P
 
 
Les Jones 123/09/2011 18:17:44
2243 forum posts
153 photos
Hi Ian,
You could look on the internet to see if you can find the data sheet on the IC used in the original controller. If you can find the data on the IC it should be possible to work out the connections. I have two of these motors and controllers but I could not find a data sheet for the IC. I hope you have more luck with yours.
Les.
 
Ian P23/09/2011 20:15:20
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Posted by Les Jones 1 on 23/09/2011 18:17:44:
Hi Ian,
You could look on the internet to see if you can find the data sheet on the IC used in the original controller. If you can find the data on the IC it should be possible to work out the connections. I have two of these motors and controllers but I could not find a data sheet for the IC. I hope you have more luck with yours.
Les.
 
Les
 
The only IC in the one I have is a programmed 28pin microcontroller a 47C241 and marked 'Byduni 45DF' as is the PCB. Life would be much easier if Bosch had used a standard motor control IC!
 
The module label on mine shows,
 
Copreci
Code 361-076
230V 50/60Hz etc
 
Googling Copreci and Byduni finds several hits mostly on forums where people are asking component values to try and repair burnt out resistors! Unfortunately whilst I can find pictures of identical boards no hits have any wiring diagrams.
 
Are the ICs in your controllers standard ICs or are they custom programmed devices like on mine?
 
Ian P
 
 
Les Jones 124/09/2011 09:26:06
2243 forum posts
153 photos
Hi Ian,
The two controller boards are I think from Hoover washing machines (Different models.) but both use the SN96517BN IC I have just had another attempt at finding data on this chip but failed. It is a 20 pin chip. I do not think it is a microcontroller as I think I would have found the data sheet if it was. I did think of feeding the field windings from a low voltage supply of about 5 volts (They are wound in quite thick wire so have a low resistance.) and supplying the armature from a variable voltage supply (Or PWM) I think it would behave like a permanent magnet motor using that method.
 
Les.
Ian P24/09/2011 10:07:11
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2552 forum posts
113 photos
Les
 
If you look at the components on the board that are surrounding the 20 pin IC you should be able to determine whether they are part of analogue or microprocessor circuit topology, athough I do think its more likely to be an ASIC or microprocessor (which will probably have a resonator or even a crystal) Even if you found the data sheet it probably would not help much.
 
I too had thought wiring the motor in shunt configuration, using DC for the field winding. I think it would give better torque and work better at low RPM.
 
 
Ian P
Les Jones 124/09/2011 14:27:12
2243 forum posts
153 photos
Hi Ian,
I do not remember seeing a crystal or resonator on these boards so it is probably not a microprocessor. I do not have any need to use these motors at the moment. If I did I think I would use a TDA1085C. If you are interested in playing round with a microprocessor based speed controller I designed one for the table drive on my X3 mill a few years ago using a PI16F876A It controls a 24 volt permanent magnet motor. The speed is sensed from an optical encoder on the motor and controls the motor using PWM. There is a serial interface on it so the PID constants can be adjusted. I have also converted the code to run on a PIC18F2431 The PIC16F876A only uses 8 bit values in the calculations. The PIC18F2431 version uses 16 bits for the calculations. You are welcome to a copy of the code to use as the starting point of a design for a washing machine motor.
Les.
Michael Horner25/09/2011 09:58:27
221 forum posts
63 photos
Hi Ian
I have bought one of those controllers using the TDA1085C mentioned by Les. I use it on a floor standing 12 speed drill, I got sick of changing belts. If only I'd known about center point drills. You mentioned using it at low speeds and would there be enough torque, I think there will but the motor will produce a lot more heat ,cannot give you any figures but my motor cuts out on big drills at low speeds because it has an in built thermal cutout which has tripped out in the past. If you want to play about with the motor use a low voltage that way you limit the power into it. If you want a very low speed you can arrange the windings in a shunt wound configureation. I cannot help with calculations my maths just ain't up to it.
Cheers
Mike.
Ian P25/09/2011 12:07:40
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2552 forum posts
113 photos
Les
 
Thanks for the offer of your software. It sounds like you have spent some time and effort into making a proper job of it (with serial interface etc) and certainly if I build my own controller I would appreciate using your cicuit and code. I know of a couple of people that use PICs so can borrow a programmer etc.
 
Michael
 
By low speed I meant low in relation to the top speed of the motor, I would reduce the speed with belt and pulleys by about 4:1 and hope the speed controller will do the rest so that it will produce enough torque at say 300-400RPM.
 
Ian P
 
 

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