Choosing a VFD?

I'm going to be buying a 3 phase mill soon, and need to power it at home. Rather than going with a phase converter, I figured a VFD would be a better option. I like the idea of being able to change speeds without changing the belt on an older Bridgeport. I'm assuming that a VFD and 240V, single phase is all I need, right?

How do I choose one? In searching, I'm finding a lot of options. Constant torque, or variable torque? I looked at one, and the manual was 420 pages! Too much info; I just want to plug 'n play. Will they power most standard 3 hp motors? Is there any way to make it show the actual spindle RPM? In low gear, the motor RPM doesn't tell me much. Can I use the device for different machines (one at a time, of course)? I have a 3 ph surface grinder that I'd like to use from time to time. Can I put the VFD near my panel, and just wire up several outlets for different machines? I see you can get a remote to mount right on the machine- are they hard-wired, or wireless?

What else do I need to know? Is there any harm in going big, such as a 5 hp unit for a 2 hp motor? Do you instant reverse with the switch on the machine, or with the VFD? Or either? Obviously, I have a lot to learn- I know one of you guys have experience here. Thanks!

Markyyyy said:

Is there any harm in going big, such as a 5 hp unit for a 2 hp motor? Do you instant reverse with the switch on the machine, or with the VFD? Or either?

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Back when I bought my first VFD the get a larger one than the motor was what was recommended. So I have done that with my other machines too.

The instant revers seems to work better with a switch on the machine. My 3PH lathe uses a switch to control rotation direction and it reverses instantly. But my Bridgeport I just use the panel buttons for forward and reverse and it isn't instant. But that could be from the way it is programed.

My first VFD was a Teco brand, it stopped working after 3 or 4 years, spent a lot of money on that one. When I changed that one out I got a Huanyang clone VFD that they sell on Ebay for not much money, bought 3 of them one for the BP, one For my surface grinder, and one for the lathe. I'm really happy so far with them. The instruction manuals kind of suck, but there is much information on the web to get you through most things.

I'd advise against using one VFD for different machines to much of a hassle, because each mahine will need both power to it and control from it, too many switches. The Ebay VFD's are so inexpensive the switch hassle isn't worth the trouble in my opinion.

The Chinese Huanyang is the "el-cheapo" option for sure, but I would pay a few more $$'s and at least get a Hitachi or equiv.
For a mill you need a phase-vector version, not a Volt/Hz type, some will accommodate both via parameter.
With using a FWD and REV switch, most will accommodate an instant change over, the VFD usually decelerates at the programmed rate, then ramps up in the other direction.
Setting the parameters is usually mandatory and no way to dodge it, even ones that have auto tuning, a little adjustment is needed afterwards, anyway.

I could talk to you in extreme length on VFDs..... PM if you want and I will get you lined out.

MaxHeadRoom78 said:

The Chinese Huanyang is the "el-cheapo" option for sure, but I would pay a few more $$'s and at least get a Hitachi or equiv.

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while that maybe, Iwould much rather replace one of my ~$85 Huanyang's that work just fine ,instead of another ~$300 Teco-Westinghouse VFDs that died after a few years.