Another washing machine motor repurpose

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#1

Hi all
I have salvaged a universal motor from my mums kaput 20 year old washing machine for a project to make something similar to a potters wheel.

Before I delved to deep into making mounting for the motor I thought I would make sure it wasnt the motor that caused the failure and wired it up using my bench power supply as a DC motor by putting the field and armature windings in series, it works fine.

My project needs to have a variable rotation speed of 20 RPM to approx 120 RPM. I can do this in the prototype with the bench power supply, at 20RPM the motor takes 900ma at 9V DC, around 8 watts and understandably the torque is very low.

I know the motor probably needs to spin faster with greater gear reduction, the motor pulley is around 20mm diameter and the main pulley is around 400mm giving a 20:1 gear reduction, therefore the motor is only spinning at 400rpm when the wheel spins at 20RPM.

My questions are:

  1. There is a dedicated chip designed to control specifically washing machine motors - TDA1085c TDA1085c and rather than build a PCB from a chip there is an enterprising Russian gentleman selling universal washing machine controller PCBs that use this chip. Its handy because it takes care of lots motor management like over current, soft starting etc. It uses the tacho output from the motor to maintain constant speed, therefore I presume it could maintain torque at low speeds (like washing machines have to to with a heavy load), is that a reasonable assumption?

[https://www.ebay.co.uk/itm/Upgraded-TDA1085C-controller-regulator-of-commutator-AC-motor-100-52mm-1pc/184090985945?hash=item2adcad85d9:g:T38AAOSwcJVeKyEM](http://Universal motor controller)

  1. If I decide to run it on DC with the motor at a higher speed but using another set of pulleys can anyone recomend a good supplier for cheap pulleys and belts?

  2. I have looked for some general specifications or tech sheets for universal washing machine motors to better understand torque curves, power output, max currents etc but can’t find anything, can anyone point me in the right direction?

Thanks in advance

Lawrie

#2

I think washing machine Motors are usually suicide wound, if you rewire it it will not need a closed loop speed controller, but it might need a lower voltage

A induction motor is the way to go

#3

Hi Joe
Its working fine as connected, it didnt need rewiring just connecting differently to run from DC, it rotates the speed I want with 8v Dc. The torque is very low though.

I took the plunge and bought a TDA1085c based controller yesterday as I want to move things along. My only concern that it still might not produce enough torque at such low speed but since the controller uses the built in tacho that most washing machine motors (if they are a universal motor motor that is) have I am hoping the feedback loop would cause the controller to increase voltage to the motor when its under load.

Just an annoying 2 week wait for delivery from Russia, should have built one myself!

Lawrie