VFD use running a 3 phase motor off single phase 220 power

Trying to pull the trigger on a VFD. As usual I am looking at the cheap chinese stuff on fleabay. I have a 1/2HP 3 phase baldor buffer running on a VFD but just grabbed a 1.5HP 3 phase baldor, now I need to power it. Kinda thinking going oversize for reliability and so I can power other 3 phase equipment I may buy. Price is not much different up to a 4 or 5 horse rating and with the thin info provided kinda want to be sure I do not over work the unit due to derating with single phase input. My choice right now is a 4HP mainly because it has a visible large aluminum heat sink.

This one http://www.ebay.com/itm/321999618145?_trksid=p2060353.m2763.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Couple advantages often you can find 3 phase stuff really cheap. The VFD offers speed control and that is very useful for buffers.

So would like to hear any experiences.

We put a 3 phase motor on a mill with single phase power. I'm not the genius to explain the VFD stuff, but I do know you lose about 1/3 of the motor's power to make the transition. So if you need 3 HP, you use a 5 HP motor to be OK.

I have 25KW 220 single-phase. It comes down a pole 600 feet away from the shop, and stops there.

So, I'm not any help.

But, lots of VFD discussions in here:

http://www.hobby-machinist.com/forums/electrical-issues-power-your-machines-shop.23/

There is a forum called CNCZone.com that has a special sub-forum just for VFD and RFC's. You can find all the answers you'll need there

Thanks guys I had already been nosing around hobby machine and practical machinist an awful lot of; that chinese stuff will explode and burn down your shop type talk. I'll look at CNC zone. Got the big Baldor today so I'm champing at the bit to get r going.

Damn Gary! It's a bummer ya don't live closer. I've got 3 phase throughout, but I've also got this.......

3 phase, Sweet but I really want to move up to a VFD for several reasons.
3 phase runs in front of my house but getting it in my shop WOWSA!

I hear ya. The power pole adjacent to my building has 3 phase and it took me $3k to run it inside my building! Although my rate is 3 cents less per KW/hr. I do plan on being here awhile. Not to mention the eclectic machine shop I'm assembling.

gggGary said:

3 phase, Sweet but I really want to move up to a VFD for several reasons.
3 phase runs in front of my house but getting it in my shop WOWSA!

Click to expand...

My last shop only had 220 into it, I inquired with my power company and they wanted something like $5k to run new feeders to my building from the pole right out front, plus what my electrician wanted to install a new panel. It'll also bump you up to industrial power rates in a lot of cases.

I'd shy away from phase converters if you can. I play around with a lot of 3ph in and out VFD's so I can't really comment on single phase in, 3 out but I know several of the units I've used are more than capable of this. I believe the power loss is only an issue with phase converters, a VFD should give you full power assuming your single phase circuit can supply the wattage.

Have you considered picking up a nice used name-brand unit? In 10 years of heavy industrial maintenance (my current building has over 300 vfd's) I've never replaced a Mitsubishi, only a handful of Yaskawa/Magnateks, more Allen Bradley Powerflexes than anyone should ever have to and all of my Schnider Altivar 525's are too new to know yet.

You will get a few cool features with a VFD over a phase converter as well. Better power factor, meaning your motor will be significantly more efficient. Less amps and lower heat. You'll also have the ability to get constant feedback from your motor. You can watch your amp draw. Ability to tune an "s curve" to act like a "soft start" and obviously the infinitely variable speeds are nice.

As a suggestion, electric motors typically don't like to much slower than their rated speeds and a just fine running faster, to a point. I did have one that got pretty angry with me at 360hz and bit back. Mostly the issue is not spinning the fan fast enough to get adequate airflow and cooking the windings.

Well I got right on this project and today it runs! Took some more web searching and interpreting the Chinlish manual to figure out the programming but the cheap fleabay unit is doing it. Actually it's bit complicated because these VFDs can do SO much to manage a motor. I got a 4HP unit to run the 1.5 HP kinda thinking it could power most 3 phase motor powered equipment I would be likely to buy. The connection terminals are pretty small and there's not much room to work The (sloppy Gary) buffing grinding center so far.



Got to the buffer because I needed to buff some of this to build wheels


That 14" abrasive wheel that will reach into the rear hub and clean up the grooves. Now I have the horsepower to run it slow and use some pressure to really clean well. Thanks for the heads up Drew I'll keep an eye on the motor temp. Still want to add a rotary speed control pot cause it's easer than up down buttons, a push forward, off, reverse switch and some other finishing details.
Mounted the big buffer to same base as as the 1/2 horse unit.

I checked into this years ago, ended up buying new motors instead. I sure paid more than that on new motors.