Anyone experienced using a larger (11kW,15hp) VFD 3 phase using only single phase in?

Hi Everyone, It's been a while.
I have an opportunity to install a system that uses a 480V 3phase 4.4kW gearmotor driven by a 11kW VFD. Everything is from SEW Eurodrive. My problem is that I don't have 3 phase available at my site without either running a new service about a mile or installing a roto-phase converter. My thought was that since smaller drives can be configured single phase in, three phase out, what is preventing a larger drive from operating in this mode. I spoke to a Shneider rep and was told that their larger drives can be used in this manner as long as the drive is sufficiently oversized to allow for the higher currents on the 2 input leads and any drive parameters that override input phase loss faults are set properly. I called SEW Eurodrive Canada and the application engineer originally told me that the 11kW VFD was not made for single phase input, then he conceded it was possible in theory as long as the drive is sized properly and that there should be no need to jumper any faults. I really don't care to install the whole system to find that there is a snag and have to rush in a roto-phase converter. Any thoughts or experience in this area would be welcome. My last strange VFD project I was helped out immensely by this site and especially DickDV. Now I'm back to the well.
thanks,
Brian Silver

current on a 3 phase line would be approx 5.3 amp and on single phase approx 9.2. Disregarding power factor in both cases. Since you are using only two of 3 rectifiers so to speak you have to derate the VFD.

The 11 kw VFD at full power draws approx 13 amp per phase - your rectifiers therefor can handle 13 amp. with only 4.4 kw load the rectifiers will be loaded to only 9.2 amp so should be just fine.

11 to 4.4 sounds pretty good to me.

You will have to dial in parameters to "tell" VFD what size motor you have on it. You will have to tell it max current (ie trip current) and you may have to adjust the DC bus low voltage parameter. I would read this portion of manual closely before I try it out.

The other thing I wonder about is the ripple capacitors on the DC bus. 3 phase rectification yields DC with much less ripple and a DC volt (RMS) approx 1.7 times AC line.
Single phase rectifier would yield more ripple and a lower DC bus volt approx 1.4 times AC line. You may have to keep an eye on your DC bus caps and may have to increase the capacitence to deal with more ripple. Good question for the factory I think.

Assuming you keep the VFD cool especially so the rectifiers I think this should work well.

Dan Bentler

Dick's advice will be valuable, but if I were you, I'd get SEW to put something in writing regarding the advisability of running the drive on single phase power. If they give it the green light and you run into problems in the future, you can pull out the document to get them on board to cover your losses. If SEW won't sign off on the application you have ammunition to go back to the bean counters at your company to get the money to install three phase power at the site.

Steve Bailey said:

Dick's advice will be valuable, but if I were you, I'd get SEW to put something in writing regarding the advisability of running the drive on single phase power. If they give it the green light and you run into problems in the future, you can pull out the document to get them on board to cover your losses. If SEW won't sign off on the application you have ammunition to go back to the bean counters at your company to get the money to install three phase power at the site.

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I agree with Steve. The VFD should work just fine but factory assurance goes a long way to headache reduction.

A roto converter can be built up using a properly sized 3 phase motor. Fairly simple and quite reliable. If you use a "large motor" you may be able to supply your future 3 phase needs with just one unit.

IF you have 3 phase on the pole outside your building and you foresee needing more 3 phase this is the time to talk with utility and see about a 3 phase service entrance. If 3 phase has to be brought in from a mile or so that just may be cost prohibitive.

Dan Bentler

The general rule about single-phasing three phase inverters is that the output capacity is cut in half. So, whatever the output rated amps are, figure 50% of that is available for the motor and load.

One other hurdle to check out is whether the SEW drive has a single phase input fault. If it does, you have to be able to turn it off or the drive would always be faulted. That's a software item.

Getting the manufacturer's blessing is always a good idea. Getting it, however, might be more work than it's worth.

Looks like I came to the right place (again). Good to see the old gang is still hanging in there. You have all confirmed my suspicions. I have found that the SEW engineer seems to be backing away from his earlier positive note by emphasizing that the drive is not rated for this application but it is possible in theory. I guess without further assurances from SEW I need to set up a test. I asked if they might be willing to test my application but I'm not holding my breath. Unfortunately it will be me personally that bears the cost if I need to create 3 phases. I am planning to retire next year and this system was going to be the backbone of a business I want to start up. Thanks for all the amazingly quick responses and I will keep you up to date on the progress.

Brian

your warranty will probably be Void if you use single phase, unless the drive is a single phase to 3 phase drive. I have done this in the past with no problem with drives, some only check 2 of the 3 phases to see if 3 phase is present. You should let your customer know what you are thinking and let them make the decision on whether to run 3 phase in, or go with a drive running single phase. If de-rated properly and if the drive is actually able to have phase loss bypassed, it should be ok.

You might consider checking these folks out. They have drives specifically to do what you want.
http://www.driveswarehouse.com/s-26...4=s-267-phase-converter-vfd&select5=&select6=

You may be money ahead by crating the 11 kW unit for future use or sale.

Buy a unit designed for single phase at your desired line voltage.

Are you using 240 and stepping up to 480 for this unit? Would consider a 240 single phase unit.

Dan Bentler

Thanks for the link and yes I need to step up to 480-500V from 220V feed.
If the system manufacturer finds that we can make this work, they stand to be able to increase their market.
If I need to replace their standard components before I turn a wheel, I will have to go it alone.
I need someone with deeper pockets than mine to take on any R&D because they stand to increase their sales and SEW will gain more sales and I take on all the risk. That's the reward I get for retiring after 30 years as an industrial electrician and going into business for myself. (that's the plan anyway if I can get these issues ironed out)

Let's see here. 11kw is about 15hp which would require about 22amps at 460V. 4.4kw is about 5.9hp which would require about 10amps max. That's less than half of 22 so it sounds like the sizing is ok. Still have to check out that single phase input fault tho.

If your plans so depend on doing this, why not get a drive that will do the job without question. Buy an ABB ACS355-03U-23A1-4+J400 and be done with it. It will work. There will be no warranty concerns. There are no fault concerns.

There is no good reason to stay with an SEW drive just because the gearmotor is SEW.

I've been running a lathe this way for over 3 years

Description

Toshiba G3 series Inverter VFD.
460 V unit rated 22 Amps output

feeding a 18 amp fla, at 240/480V, 5 hp 1725 motor configured for 240V

No loss of input leg setting to change with this model Toshiba.

The Drive is set to provide 440 Volts at 120 hz. Yup, 120 hz! The motor sees 240 V at 60 cps. and would see the full 440 v at 120 cps if programmed to do so.

The drive is set to high limit frequency at 100 hz, because I have no need of running the lathe faster than that.

The drive is supplied 440V from a 240X480 delta /wye dry type x former that is being fed off single phase 240V lines, and outputs single phase at 440V.

It all works just fine!

IF you expect to use the full load amps continuously, sizing the rectification diodes (2:1 rule of thumb) is a very good idea.

I think you are in good shape with what you have.

If someone else is buying the hardware, or you need to answer to up time and safety issues. I'ld say you are still good, but better to let someone else take the engineering side.

Cheers

Sliver said:

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...a system that uses a 480V 3phase 4.4kW gearmotor driven by a 11kW VFD. ...

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It should be possible to connect stator to "delta", now it's in "star".
If you connect stator in delta then voltage will be 3x~277V, much better if you have only 1x~277V supply. Of course current will be bigger.

Because you use 1ph power supply then you need to take bigger VFD. You should find information in VFD manual.

PS: my natural voltage is 400/230VAC - European standard, so maybe my information are not correct in 480,100VAC world.

You will have to run the motor on 230V. If you size the drive properly, which two incoming leads will make a difference, then it should work.
But, a rotary phase converter will not work with the drive.
Sincerly,
Jade York
989-922-0043
www.repairzone.com

Going back to the original posting, it appears that the drive is a 480V unit at least double the required ampacity which allows for single-phasing the input.

Under those conditions, a motor of 480V, 460V, 415V, 400V, or 380V could all be used. There is no need to use a motor configured for 230V.

If the SEW motor is nameplated 50hz and 230D/400Y, be sure to use the 400Y configuration and put the nameplate data for that voltage into the drive. If the motor is dual labeled for 50 and 60hz, I would recommend going with the 60hz data. The voltage will then likely be 460 or 480V, as well.