efficiencies of appliance 3-phase brushless motors?

Oh, absoposolutely. But there's still the size, material, and cost waste...

Of course I found these units two weeks _after_ I picked up and installed the traditional ones in our house...

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Reply to
danny burstein
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Home Depot has a 5kbtu window AC unit for around $100 or $130; I forget exactly.

I went ahead and took apart my broken Sears/Kenmore front load washing machine (turns out it has broken shocks, among other problems) and pulled out the motor. It's a J52AAC-0102 if anyone's curious.

I was about to ask if anyone knows of circuits to play with 3-phase motors but I found something already.

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Unfortunately that MC3PHAC controller is at End Of Life due to low sales.

Michael

Reply to
mrdarrett

Ebay has some cheap VFD controllers starting at ~$50 (for 220VAC) Single phase in, three phase out.

Reply to
default

At least 10 or more years ago the heat pumps and probably other heating/cooling systems moved to speed controlled motors. There is a way where the motors start up slow to move the air that is sort of a way to cheat on the 'government efficency' numbers.

Reply to
Ralph Mowery

It is not so much if purging works or not. For around 20 or 30 years it has been illegal to dump any refrigerent into the atmosphere. The claim by the government is that it depleats the ozone layer. There is a big fine for doing that.

Reply to
Ralph Mowery

The R134a refrigerant can be bought by anyone and they sell one pound cans for recharging car AC's. Or you can go on-line and order a 30 lb cylinder without a license. (unlike R-30)

The info I found said it was a greenhouse gas, but not ozone depleting. The information that shipped with it gave the reason for purging to be: moisture freezing in the evaporator valve and blocking it. (the "valve" is often just a length of copper capillary tubing) The AC people said it is necessary to prevent acids from forming and destroying the compressor.

I've no doubt that it is better to recycle it, and better to draw all the moisture and air out with a pump. But given the number of cars on the road leaking it by the pound, I figure my one-time loss of an ounce or two shouldn't matter.

AND if you still want to say it is wrong, read the label on a can of computer "Dust-Off." There are people on Utoobe who buy that stuff because it is cheaper than the same stuff labeled as a refrigerant.

The units do have desiccant dryers in the compressors to eliminate moisture.

Back in the day... the EPA forced AC contractors to buy some pretty damn expensive refrigerant recovery equipment, to deal with the hassle of sending it off to be recycled into fresh clean stuff, and to take classes to learn the law and how to recycle to get a license. That same regulation is capitalized by AC contractors today that see DIYer's cutting into profits that they think are rightfully theirs. Now it is political, cans of "dust-off" not withstanding. The other faction with a vested interest are the thousands of auto-repair businesses who don't want to spend the money on specialized equipment or hire specialists to work on AC.

Reply to
default

Huh? That doesn't sound believable. An AC runs and uses power which is easily measured in watts, can be used to cool water or air which have known caloric absorption rates for measurable temperature rise/fall... which, in turn, can be used to calculate power doing useful work.

That is how microwave ovens are tested for efficacy. How much temperature rise in a known quantity of water is produced in a specific amount of time. An AC is playing the same game, and the same measuring techniques can be used to test efficiency. The testing equipment would cost a little more.

Soft start is generally just easier on the mechanical components and eliminates the large power spike starting induction motors create. Eliminates the centrifugal switches, and is easier on the power source (wiring and circuit breakers)

Soft start can also provide feedback in AC systems to avoid overloading compressors with a lot of back-pressure when starting. (eliminating the pressure switches or thermal overloads AC's and refrigerators currently use)

Are you sure you aren't confusing this with Auto computers programmed to run lean in testing but richer in normal driving?

Reply to
default

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