Why Use a 3 Phase Motor in a Washing Machine?

On a project I did last year, a 1/2 horsepower single phase motor cost $100 more than the same 3 phase motor. I used the 3 phase motor with an inexpensive VFD.

Because in the end it comes out cheaper for washing machines. Remember, electronics are cheap now days so the multi-speed motor becomes a large part of the costs.

Maybe it's just a two speed motor?

http://www.manualslib.com/manual/409135/Frigidaire-Fafw3577kr-Affinity-Front-Load-Washer.html?page=8#manual

Its a multi speed, since the motor controller changes the frequency of the current to control the speed.

I remember from power electronics that a 3 phase motor speed is dependent on the frequency, since each phase is 120 degrees out of phase from the other two; the stator turns to keep up with the rotating magnetic field.

Back when I was in college, it would've been less expensive and more reliable to use a transmission to control the speed vs electronics and a 3 phase motor. I get it that nowdays, it's less expensive and more reliable to control the motor speed with electronics.

GA for coming up with the manual on the unit. You got the correct model!

I think using a 3 phase motor with a VFD is done to eliminate the mechanical transmission which used to be the most expensive and vulnerable component in a washing machine

I think you're right. When the washer wouldn't drain, I thought it might be the transmission, but there isn't one on this washing machine.

So using a VFD, the speed is controlled by frequency vs a mechanical transmission. Less cost due to a simpler manufacturing process and probably less parts.

Spot on!

Also, the VFD allows many speeds both for washing and spinning plus simple electronic reversing!!! Mine goes up to 1600RPM when spinning....I am sure there are even faster machines out there.

I just realized that a front load washer may not be able to have a transmission. The drum is very large and it's belt driven from the motor. Due to the size of the drum (depth), the pulley for the belt is right at the back of the unit - no room for a transmission behind it.

I guess a transmission could be incorporated into the open cavity below or above the drum (in one of the four corners), but it wouldn't be the same as the top load washer transmissions, which attach directly to the drum.

I'm curious to know what type of motor drive line and load filter or reactor is used.

I don't see it in the diagrams.

Speed control management and energy savings.

Oh, well. There goes my normal source of 110V motors for tinkering!

Yeah - but these new 3 phase ones are normally permanent magnet devices, so you can quite easily convert them into 3 phase generators, lots more scope for tinkering.

For the same reason most sanitary mixing tanks have a three phase motor on the mixer and a 120VAC VFD to run them. Where I work we build about a hundred of these every year and it is the lower cost way to go.

Many of us got caught by the same design flaw in the $mall controller board(dollar sign added for emphasis). BTW: I seem to recall that the motor also carries a 400 VAC rating on it--increase the voltage while producing 3-phase and provide the same power with smaller gauge wire.

As mentioned earlier, speed control, inherent reversing capability and energy savings. The motor efficiency it typically a lot better, as in 10-15% better, which is a large part of the energy consumption of a washing machine. Then also when running the pump, which is a goodly part of the typical cycle, you can vary the flow without using a valve and save energy by reducing the losses associated with running the pump at full speed and choking off the flow. The energy saved improves their overall energy efficiency rating of the appliance, which in some areas is now mandated to be at minimum levels unattainable with older less expensive designs.

In the same line, I have a GE 175D5106G036 3 phase motor and want to use it in a band saw. I have been looking everywhere for the layout of the pins and haven't found it yet. Any help will be greatly appreciated. thanks you all.

Use a sensitive Ohm Meter to identify the fields and their connections. Its not rocket science!

This should help:-

How to Check Winding Resistance on a 230/460V, 3-Phase, 60Hz

Thanks a lot!

That GE motor is only about 1/2HP and is not designed to be used on a machine like a band saw, it will get full of dust and debris and fail quickly. They purposely don't give you the pin-outs because they don't want the liability of someone using it inappropriately like that.