Repurpose motor help

Thread Starter

schoolfire

Joined Feb 13, 2021
1
Can i use a old washing machine motor. Its a 3 phase 195 v 3amp 285 htz variable speed induction motor. My area has 120v 60htz power. I think my understanding is flawed.
Running a 285 htz motor on only 60htz means that i will not get the max speed out of the motor. That's fine, its going to be a bench sander and will not need speed control other than to keep it from killing itself. Torque will be reduced as well.
I can use a dimmer switch to reduce the voltage to the motor ( and have some speed control) and use a capacitor to get the needed 3 phases.
The motor model # j52hrb-0106 out of a whirlpool washing machine ( part number 8540132). Motor control board was bad and got it for nothing.

Any help to further my understanding of using this with out a VFD would be helpful.
 

MaxHeadRoom

Joined Jul 18, 2013
23,092
The rpm depends on the pole count, it could well be a 2 or 4 pole motor, just ran at higher rpm on the W.M. controller. If truly a higher pole count, then you will not get a really usable rpm on 60Hz.
Using on 240v would be the better option.
Max.
 

MisterBill2

Joined Jan 23, 2018
8,740
The 285 Hz 195 volt spec tells me that it is a brushless motor from a more modern wash machine. You need to recover the electronic driver module to use that motor, or build one to replace the one that you do not have. That is not a simple task, by the way.
 

MaxHeadRoom

Joined Jul 18, 2013
23,092
The 285 Hz 195 volt spec tells me that it is a brushless motor from a more modern wash machine. You need to recover the electronic driver module to use that motor, or build one to replace the one that you do not have. That is not a simple task, by the way.
The OP mentions Induction Motor, if it is, it most likely was the version fitted with a VFD.
The modern version use a Fischer-Paykel outrunner motor which is fitted to the bottom of the tub, i.e. no gear box.
But the OP mentions "old Washing Machine"
A pic of the motor might help!
Max.
 

MisterBill2

Joined Jan 23, 2018
8,740
The OP mentions Induction Motor, if it is, it most likely was the version fitted with a VFD.
The modern version use a Fischer-Paykel outrunner motor which is fitted to the bottom of the tub, i.e. no gear box.
But the OP mentions "old Washing Machine"
A pic of the motor might help!
Max.
I am guessing an earlier front loading machine, the early ones had more complex drive systems before they were engineered for minimum cost not best performance. Rear bearing assembly and a horizontal tub and electronic reversing and speed control. Easy with an electronic drive. And an induction motor can also be a brushless DC motor when you add the inverter/driver package. They do not have to be PM motors to be brushless.
 

strantor

Joined Oct 3, 2010
5,543
We discussed these motors a few months ago (see here, posts 21 & 28) they are 2pole 3ph induction motors. You should be able to run them with a VFD. If you have 3ph power available (from phase converter or 3ph service) then you should be able also to run them at 60Hz as long as you use a 3ph transformer to step the voltage down to the appropriate level on the V/Hz scale (41V @ 60Hz?). Note that it will have very little power if ran that way.

You cannot run this on 120V single phase. You might get it to go roundy roundy and/or make strange noises and excessive heat, but it won't power your sander without a 3rd phase. Also you can't control the speed with a dimmer switch. Also this is a high speed/low torque motor which is probably the opposite of what you need. It's a shame you washing machine motor isn't the more normal brushed/universal motor, as with that you actually could control it with a dimmer switch (a robust one meant for inductive loads), at 120V/60Hz.


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MisterBill2

Joined Jan 23, 2018
8,740
OK, that set of pictures explains it all. The motor is intended for use with an external inverter ONLY. And quite likely the winding reactance is not high enough to limit the current at 60 hertz.

And the answer for Max, NO, a permanent magnet field motor IS NOT an induction motor. An induction motor works because the varying magnetic field from the stator winding induces a current in the copper windings buried in the rotor. That is the reason that they used to be called "Squirrel-cage" induction motors. It is the INDUCED magnetic field that drives them. PM motors do not use an induced magnetic field in the rotor.
 

strantor

Joined Oct 3, 2010
5,543
OK, that set of pictures explains it all. The motor is intended for use with an external inverter ONLY. And quite likely the winding reactance is not high enough to limit the current at 60 hertz.

And the answer for Max, NO, a permanent magnet field motor IS NOT an induction motor. An induction motor works because the varying magnetic field from the stator winding induces a current in the copper windings buried in the rotor. That is the reason that they used to be called "Squirrel-cage" induction motors. It is the INDUCED magnetic field that drives them. PM motors do not use an induced magnetic field in the rotor.
I'm 100% sure Max didn't need the lecture on the difference between permanent magnet and induction. His comment was in response to yours:

an induction motor can also be a brushless DC motor when you add the inverter/driver package. They do not have to be PM motors to be brushless.
Maybe you could provide an example of a BLDC induction motor? I'm curious as well.

A BLDC can be controlled by varying the voltage applied to it, same as a typical brushed DC motor. This happens naturally. If it were an induction motor you would have to force that behavior.
 

strantor

Joined Oct 3, 2010
5,543
It certainly seemed in post #6 that Max was not believing that a PM bldc motor was not an induction motor. That was what I was responding to.
Yeah post #6 wasn't very clear. Still, we've coexisted on this forum for almost a decade and I know him to be an expert in this field.

Back to the topic of your proposal of the existence of induction-BLDC, I've been giving it more thought and I didn't get any closer to agreement. Part of the definition of a BLDC is that it's a synchronous motor. An induction motor can't be synchronous. Another part is that they're electronically commutated. When you "add the inverter/driver package" (VFD) you're not adding electronic commutation. Even if you add an encoder, there is steady state slip between the feedback RPM and the output frequency, so it is not commutation.

I think, when you "add the inverter/driver package" (VFD) to an induction motor (even if supplied with DC direct to the DC bus), what you end up with is an induction motor with a VFD, not a BLDC.
 

MaxHeadRoom

Joined Jul 18, 2013
23,092
And the answer for Max, NO, a permanent magnet field motor IS NOT an induction motor. An induction motor works because the varying magnetic field from the stator winding induces a current in the copper windings buried in the rotor. That is the reason that they used to be called "Squirrel-cage" induction motors. It is the INDUCED magnetic field that drives them. PM motors do not use an induced magnetic field in the rotor.
I am perfectly aware of the construction and operation of an Induction motors, having worked with them for 60yrs!
Over the course of this period, I cannot think of a motor technology I have not worked with.
In the case of the OP's motor, if 240v 1ph is available, then there are several VFD options in order to run it. It is an Induction motor. Not P.M.
BTW, a BLDC motor and a AC 3ph synchronous motors are constructed identically, just that the BLDC has only 2 winding's energized at any one time, as opposed to the 3ph version. Both have a P.M. field.
I repeat, a BLDC motor does not obtain its field from induction!
Max.

BLDC commutation:
 

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MaxHeadRoom

Joined Jul 18, 2013
23,092
One other point on the motor, is if it a simple two pole induction motor and is limited to a certain high RPM range, it usually means that it does not have sufficient core material to allow it to be ran on a low frequency such as 50hz/60hz.
This is why motor manufactured in this way such a H.S. spindle motors have the VFD set for a minimum output rpm level, otherwise a burn out of either the motor or drive occurs. due to low inductive reactance at below a certain RPM/Hz point.
Max.
 
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