Author Topic: Washing Machine Motors  (Read 1269 times)

Offline RussellT

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Washing Machine Motors
« on: March 27, 2018, 05:22:46 AM »
Hi All

I've just dismantled a couple of washing machines because I wanted to see if a stainless incinerator made from the drums lasts better than the galvanised ones from the garden centre.

So I have two washing machine motors on the bench.  I was surprised to see that these appear to be induction motors and on looking at the plate it seems that these are probably driven by some sort of VFD.  They are marked 195V 315Hz 17,500rpm.

I'm assuming that the 195V makes these more or less useless for home use.  Can anyone enlighten me before I scrap them?

Russell

Offline russ57

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Re: Washing Machine Motors
« Reply #1 on: March 27, 2018, 05:41:17 AM »
If they are 3 phase, I guess you could use a vfd to drive them. I think you can set the output voltage as well as the frequency.

Or just a step down transformer.


Russ


Online John Rudd

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Re: Washing Machine Motors
« Reply #2 on: March 27, 2018, 05:57:54 AM »
Russell,
Dont you have the control boards from the washing machines? I would have thought the speed control for the motor may be integrated within?
Have you a photo of the motor showing its leads and/or the control board?
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Offline RussellT

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Re: Washing Machine Motors
« Reply #3 on: March 27, 2018, 08:55:10 AM »
Thanks for those thoughts.  It hadn't occurred to me that they might be 3 phase - although now Russ has suggested it it seems obvious.
I have got the controller boards but I'm sure I couldn't work out what's they're doing or how to influence it.

I've looked at the motor connections as John suggested and there are five wires.  Two of them are connected to a speed sensor on the end of the motor and the other three show 6.5 ohms between any pair - confirming I think that they're 3 phase motors.

I'm attaching pictures of the controller boards.  They are slightly different but the motors are identical.  Both boards have six large 3 lead components under the big heatsink and one has a big rectifier on the heatsink too.  The transformer looks to be part of the output but I haven't checked the board traces or the wiring loom to confirm that.

I'm guessing that somewhere on the board something is turning the big transistors on and off to produce 3 phase. :scratch: :scratch:

Russell


Offline hermetic

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Re: Washing Machine Motors
« Reply #4 on: March 27, 2018, 01:48:54 PM »
If you have saved the wiring harness as well, you need to isolate the wiring between the motor and the speed control board. You will find that there is forward, reverse and variable speed available. It all depends on whether there is a wiring diagram available, and the type of programmer the machine uses. Early machines were rotary mechanical types, later ones are all digital, and a bit more complex. By a process of deduction, and some VERY CAREFUL experimentation, it should be possible to see where the feeds need to go to produce forward, reverse, and probably a couple of spin speeds, or even infinitely available spin. Time to learn some basic electrickery!

Offline pycoed

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Re: Washing Machine Motors
« Reply #5 on: March 28, 2018, 07:02:25 AM »
This bloke's Youtube channel may help?

Online John Rudd

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Re: Washing Machine Motors
« Reply #6 on: March 28, 2018, 10:02:56 AM »
An informative video, but its aimed at universal motors rather than poly phase induction motors.
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Online awemawson

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Re: Washing Machine Motors
« Reply #7 on: March 28, 2018, 10:33:29 AM »
An excellent well presented video - extremely clear  :thumbup:
Andrew Mawson
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Offline RussellT

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Re: Washing Machine Motors
« Reply #8 on: March 29, 2018, 08:01:45 AM »
Thanks for all the thoughts and advice. :nrocks:  I've seen a few YouTube videos on washing machine motors but none on motors like these.

One of the interesting things is the motor speed sensor - interesting because the speed of a 3 phase motor should be fixed by the frequency - so there is presumably some feedback - possible for acceleration.  I think that makes hacking the original drive boards extremely difficult - well beyond me anyway. :scratch: :(
 
It would probably be easier to reproduce the output stage of the drive board and control it with a microcontroller.  It might be possible to buy an off the shelf drive.

I don't have any immediate use for these so they may yet go to the scrap man.

Russell

Offline philf

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Re: Washing Machine Motors
« Reply #9 on: March 29, 2018, 08:59:21 AM »

One of the interesting things is the motor speed sensor - interesting because the speed of a 3 phase motor should be fixed by the frequency - so there is presumably some feedback - possible for acceleration.

Russell

Russell,

You're right about the speed being governed by the frequency but the drive can vary the frequency and phasing to give you variable speed and direction.

Phil.
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Offline David Jupp

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Re: Washing Machine Motors
« Reply #10 on: March 29, 2018, 10:25:51 AM »
And with feedback provided to the drive, there are less assumptions about what the motor is doing.  Better control is possible than without feedback.


Offline JHovel

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Re: Washing Machine Motors
« Reply #11 on: March 30, 2018, 11:13:17 AM »
I would think that these are very useful motors indeed. If you were to buy a low-cost VFD (like a Teco or Huanyang), you would be able to control everything you wanted to in order to use it for a spindle drive with a very wide range of speeds. These washing machines run at very low speed when washing and at high speed when spin-drying.
The sensor is probably too difficult to integrate into the arrangement, but as mentioned, it is less necessary than in a washing machine. There they are used to recognise uneven load distribution and stop the drum at a particular position to let the washing fall into a new more balanced distribution. I've watched our washing machine do that and was amazed at how that was done.
And yes, you can adjust the maximum output voltage on VFDs. See if you can find out the maximum motor current for these motors and you would be able use them for spindle drives of some sort - drill press, lathe, mill etc with very good speed adjustment.
Cheers,
Joe

Offline RussellT

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Re: Washing Machine Motors
« Reply #12 on: April 10, 2018, 03:55:12 AM »
Thanks for all the ideas and suggestions.  I did look at the price of an inverter drive and decided that the motors were going to the scrap man.  If anyone is already using a VFD in the workshop these would probably be very useful.

If anyone wants to find a similar motor these were both from Hotpoint washer driers - or I still have two for a few days at least.

Russell

Offline Will_D

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Re: Washing Machine Motors
« Reply #13 on: April 15, 2018, 07:39:35 AM »
This bloke's Youtube channel may help?

That is a great tutorial on electrical motors in general. Highly recomended. I learned a lot!

Engineer and Chemist to the NHC.ie
http://www.nationalhomebrewclub.ie/forum/