Siemens VFD

In our 6x12 three roll mill, we use a Siemens Micromaster 440 VFD. The input power is 3 phase, 208V, 60 Hz. Can I connect it directly to a single phase 220V, 60Hz power supply?

Ken

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No.

I don't know what a three roll mill is, but have you asked Siemens?

Martin

You cannot generally operate 3-phase equipment on single-phase service. You can "fake" the other phases using a phase-maker. They're noisy electrically, and in my experience prone to long-term failure, but they do work. A motor-generator setup can accomplish the same thing.

You might luck out and be able to convert the equipment to 1-phase. Sometimes, it can be as simple as changing the taps on the equipment's main power transformer. I am not familar with the equip, so you'll have to ask someone who is.

Either way, if you can run it on 1-ph, it probably won't be as efficient, or will require a higher amperage than it would on 3-ph (which makes sense). I mention it only because there is the possibility the 1-ph service might not be sized appropriately.

Maybe. Check with Siemens. Some of the smaller VFDs (Siemens A-F?) can operate from single phase, but you may have to derate the output power.

Best regards, Spehro Pefhany

dunno power rating, too lazy to google.

1. if its 208V line-neutral, then the DC bus will be about

in this case, you really need to set up the input rectifier as a voltage doubler - connect the neutral wire to the center point of the DC Bus capacitors (there will be 2 sets of caps in series). This forms a voltage doubler, so you will get about 650Vdc or so.

I have done this many times.

1. if its 208V line-line then the DC bus is about 208*sqrt(2) ~ 300Vdc. In this case, it will run from 220Vac.

Regardless, there will be a lot more ripple on the DC bus, and the input rectifiers will get more of a beating (the doubler is worst of all, as there are only 2 diodes c.f. 4 for scenario 2, and 6 in a 3-phase configuration). in practice this means you cant suck as much power from the mains - about 2/3 for scenario 2, and about 1/3 for scenario 1.

Cheers Terry

Ink Maker snipped-for-privacy@torreyhillstech.com posted to sci.electronics.design:

It may work. If it does you should derate the thing to about half power. Feeding it properly with a phase converter (rotary or static) is a better way to go.

Yes you can hook any vfd up to a single phase 220V and up. You have to size the vfd about 50-60% higher than the rated motor hp. Check your manual it should show you the right line side terminals to be used.

Check your documentation, our Mitsubishi VFD takes in 3 phase 208V and single phase 230VAC, if the Japanese do it, I'm sure the Germans do as well =)