Thread Number: 35415
3-phase inverter drives (efficiency)
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Post# 528884   7/5/2011 at 17:08 (4,758 days old) by arbilab (Ft Worth TX (Ridglea))        

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Ad copy seldom goes into technical details beyond giving a feature an exotic marketing name meaning nothing substantive. But is anyone usine 3-phase inverter drive in home laundry machinery?

5 years ago I 'invented' 3-ph I-drive for efficiency and modulation in residential refrigeration. Not knowing it was already invented and in limited use, just that 3-ph motors are much more efficient than single phase. My AC guy told me they were notoriously unreliable, that the electronics are lucky to last a season. Well yeah, it's a rough environment. I had already addressed that, mounting the power parts on a ceramic return-gas manifold, around 50F non-conductive infinite heatsink but still has to be isolated from atmosphere to prevent condensation. (Thought of everything.)

But even if it hadn't already been invented, I didn't have the $1/2M to patent and develop it, so it was just an exercise in imagination. For myself, I'm not sure the reliability shortfall would be worth the electric savings in home laundry. Enough problems with electronic washer modules as it is, the savings is dimes, the replacement module is hundreds.

Post# 528888 , Reply# 1   7/5/2011 at 17:25 (4,758 days old) by DADoES (TX, U.S. of A.)        

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My washer, dryer, and dishwasher have 3-phase motors.


My parents' house has 3-phase air conditioning.

Post# 528936 , Reply# 2   7/6/2011 at 00:19 (4,758 days old) by arbilab (Ft Worth TX (Ridglea))        

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3ph dishwasher? That's over the top. But the more practice they get doing it, the better it gets.

My FL is DC tach controlled. From 1998, before the 3ph chipset was invented. I'm not nervous about the electronics. Shoot, the motor never even gets feelably warm, so how much power could it possibly be wasting? (Yes, I take the panel off and feel the motor after it's run. I'm funny like that.)

I've only lived in one house in my life (1957) with 3-ph supply. It only ran the central air. When it comes to inverters, the GREATLY added parts count can easily outweigh the electric savings. Specially in the days of cut reliability corners. As above, one module replacement wipes out years of savings.

Post# 528947 , Reply# 3   7/6/2011 at 01:08 (4,758 days old) by dj-gabriele ()        

The refrigerator at my parents is inverter based, a Candy of some sorts, I still didn't see it in person. It's very energy efficient and cost only a little more than a standard fridge.

Also our A/C is inverter based but this time it is all D/C current based, also the internal units as this way it's more efficient than an A/C based inverter machine.

Anyway, if inverter based 3-phase machinery were less reliable than mono phase/DC motors, then 90% of all industrial stuff would continuously be out of order!

Post# 528952 , Reply# 4   7/6/2011 at 02:16 (4,758 days old) by arbilab (Ft Worth TX (Ridglea))        

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DJ, industrial stuff has real 3-ph to start with. A 3-ph motor is nothing more than 3 copper windings. Not even a capacitor or start switch to go wrong.

It's when you make 3-ph out of singlephase that the parts count goes up and the reliability goes down when it's done in today's cutcorner manufacturing environment.

Also, a DC motor happens to be 3-ph, mechanically commutated. Unfortunately, mechanical commutation is not practical within a sealed refrigeration system. It is within a laundry system, I haven't had a problem with mine for 13 years.

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