[SOLVED] Controlling a Washing Machine

I am designing a new control circuit for my washing machine. It is an LG wf-650 automatic washing machine. What I can't understand is how to switch from WASH to SPIN. There are no electrical means to switch. The motor agitates when the capacitor is switched from one phase to other. But how to perform the spinning? Please help!

In SPIN Motor speed will be high like 800 RPM to 1000 RPM. I think you need to control the power to motor.

Rather unusual that a single phase induction motor is used with variable speed. The usual options are DC motor or VFD, but that's no possible with single phase capacitor motor.

Perhaps someone who has this machine can tell.

Okada said:

In SPIN Motor speed will be high like 800 RPM to 1000 RPM. I think you need to control the power to motor.

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Thank you for your answer. There is no spin motor. Only one motor for agitating and spinning. The wiring diagram shows all the wires that comes to the controller. When direct power is given, it rotates clockwise and when the capacitor is switched to the other winding it rotates anticlockwise.

I cannot spin the basket using electrical means. The wiring diagram doesn't say anything about spinning.

FvM said:

Rather unusual that a single phase induction motor is used with variable speed. The usual options are DC motor or VFD, but that's no possible with single phase capacitor motor.

Perhaps someone who has this machine can tell.

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I appreciate your answer. But there is no single phase motor here. The diagram clearly says the motor is three phase. The third phase is obtained via capacitor series. The capacitor is visible and separately mounted within the machine.

The control board does not have any large capacitors. (Which I belive does not perform any inverting as inverters need capacitors and IGBTs)

But there is no single phase motor here. The diagram clearly says the motor is three phase.

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I can read the schematic. We call these motors usually single phase motors because they are connected to single phase supply. Subtype: Permanent-split capacitor motor. The capacitor circuit involves that it can't be effectively driven by variable frequency inverter.

FvM said:

The capacitor circuit involves that it can't be effectively driven by variable frequency inverter.

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So are you suggesting that by increasing the speed, I could go to the spin cycle?

The schematic doesn't give me any spin option.

The washing process is made by powering the motor windings for less than 1 second per turn. What occurs is that the magnetic brake is in general connected electrically to the water pump ( this way manufacturers save 1 switching device ), that means, energizing the brake, releases the basket to spin and just during draining process is when you can see the basket turning at the maximum speed, which no concidentally is when happens the centrifugation. Nothe that the brake is needed to quickly stop the basket during washing process, allowing fast switching between colckwise and anticlocwise directions.

The washing process is made by powering the motor windings for less than 1 second per turn.

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I thought something like this. Does the machine provide a speed sensor or a feature to detect emf frequency? Otherwise you would observe considerable speed differences depending on the loading.

I presume that just a poor estimate is made based on the water level. Considering that the clothes fabric will absorb the whole humidity and its relative weight are not too higher than water, this could give a gross approximation of the net weight inside. For example, the model I had in home have the possibility to set up 3 water levels that are detected by a cheap pressostat kind sensor with 3 output contacts.

andre_teprom said:

The washing process is made by powering the motor windings for less than 1 second per turn. What occurs is that the magnetic brake is in general connected electrically to the water pump ( this way manufacturers save 1 switching device ), that means, energizing the brake, releases the basket to spin and just during draining process is when you can see the basket turning at the maximum speed, which no concidentally is when happens the centrifugation. Nothe that the brake is needed to quickly stop the basket during washing process, allowing fast switching between colckwise and anticlocwise directions.

Click to expand...

Wow!Got it. Thank you so much!!!! :thumbsup: