VFD as 3Ph shop supply

Iggy, couple of questions about your 3hp VFD. I have three phase from the utility company and would like to use the VFD on my lathe (LeBlonde, 13" 2hp, I think) simply for speed control and 'quick-stop'.

1) will your 3hp VFD take three phase input? 2) will a 3hp VFD have issues with a 2hp motor (mismatch)? 3) you don't list a price?

Thanks, Ivan Vegvary

Ignoramus7868 fired this volley in news:VaKdneF165BA5RHUnZ2dnUVZ snipped-for-privacy@giganews.com:

The wiring would be there, regardless of what was running... the VFD would "sense" all the wiring unless I put each motor's switch at the VFD.

No. The ordinary mode would be one at a time, but I can see some "group" scenarios where three people might be working at once.

I started thinking about my R2E4 in this light, and realized, a VFD probably isn't a good candidate for driving even it, alone, unless I made some fairly significant mods to the machine.

Presently, it controls (and reverses) the motor through contactor switching. If I had to protect the VFD against that abuse, I'd have to modify the mill so that its control signals controlled the VFD, instead of the contactors.

My goal is to get the machine working properly as completely stock as possible. I will have to move one single-phase input to get both DC supplies running off a single phase. Then, the only component seeing

3-ph will be the spindle motor.

Only after the mill is healthy as-is do I want to start upgrading it to more current technology.

So, probably, my RPC is still the best candidate for driving it for the time being. Three or six HP of idler (switch selectable) for a

2HP spindle ought to be enough, even with instant-reverses.

LLoyd

Multiple speed setting options:

- Variable with a potentiometer

- Several speeds can be pre-programed and selected with switches

- You can enter the new speed / frequency on the VFD's keypad

As for speed changes, they can be instant, or they can occur at the programmed ramp up or ramp down rate.

>

1- The VFD's Iggy has accept single or three phase input. 2- I have the 3HP VFD running my 1HP Bridgeport without issues. 3- That's a question for Iggy.

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Yes, it was designed for 3 phase input.

No, but you may need to do some extra programming for motor protection features to properly function.

What is the voltage rating on your motor, 230/460? Or just 230?

$100 for a fully functional 3 HP VFD. I test them prior to shipping. Shipping will be $12 or so depending on destination.

The 30HP Yaskawa and Emerson drives I mentioned are 3 phase drives that will run happily on single phase, and they're certainly not unusual in that regard.

Pete C got it more right than I did. Also, the drives include brake resistors built in.

It's nice to see people talking sense rather than the reflex "it'll blow the VFD to pieces if you even think about more/less than one motor" etc.

The setup I'm running at the moment is here:-

Total cost was £80/$120 of which the VFD was £10/$15 :-)

Currently I've got the surface grinder connected to it (I needed to get it running to make some bits flat!). The three grinder motors are all direct-online starting. The wheel motor does cause the VFD to current limit on startup because I've got it set up fairly conservatively, but it doesn't cause any problems.

I intend to connect the HLV, 48"x10" mill and a drill press to it as time goes on. It'll use the permanent three phase distribution I'm putting into the workshop for the time when I can afford to get the utility to give me three phase directly (4-5 years).

Regards Mark Rand RTFM

You could do as a friend of mine did. He has one VFD running a lathe and mill which are sitting side by side. Right at the VFD he has wired in two three phase contactors, with a control switch for each machine. When he runs the mill, he flips the switch to "mill" and sets the speed with a potentiometer. Likewise for the lathe. He has a control box with the speed pot and stop button on a cable that he can hang on the machine he is running at the time. Only down fall is he can run only one machine at a time, but in a home/hobby shop it should not be a problem. You do not want to switch the outputs from the VFD under power. Most VFD's don't like it! Greg

Iggy, I'm very interested. Got the info from the nameplate. It is only a

1HP motor. Is this a deal breaker? The motor is wired at 220 (440 optional) and consumes 3.18 amps at 60 cycles. It has a service factor of 1.15. Hopefully your 3hp VFD will drive a 1hp motor.

The price is right. Please contact me off-group. Ivan Vegvary ivan at reelart dot us

Thanks, Ivan Vegvary (a proud Hungarian escaping Russian occupation in

1949).

I would go with RPC.

I think most drives will give you a fault if not connected to a motor. The drives have settings for motor rated current and overload protection. How many machines do you plan to have running at the same time? We have multiple machines at work where 1 VFD is used multiple motors, but only one motor runs at a time selected by contactors. You can run multiple motors at the same time from 1 VFD but it might fault the drive if you switch one in and out of the circuit while running the other.

If you plan to only run 1 machine at a time, you can buy 1 VFD and switch it between the machines with plugs, manual switches, or contactors. If you plan to run 2 machines at once, you could get 2 VFD's etc. This way you'll be able to take advantage of the VFD's speed control, acceleration and braking features plus share a few drives with multiple machines.

RogerN

Ned, can you tell me which of those drives are of this kind, I am personally very interested. Thanks a lot. If I missed something, I apologize.

I

Unlike most mfrs, who make you ask, Yaskawa supplies documentation on powering their drives on single phase. This is one for the F7 drives:

$file/AN.AFD.15.pdfIt shows recommendations for up to 60HP motors at 240V and 200HP for

480V drives.

The Emerson/Control Techniques drives I installed were SK series. Emerson makes you ask for sizing recommendations.

Last I knew, most of the Mitsubishi drives would also run single phase, but, like Emerson, you had to ask to be sure.

The extra motor idles, and absorbs surges that would trip the VFD. Very much like what happens when one uses the same motor as a RPC.

Joe Gwinn

But the motor will operate as an RPC *without* the drive. The VFD isn't adding any functionality beyond that offered by a couple capacitors, or a pull rope on the motor's shaft.

His VFD should drive anything from 3HP on down.

This is unlike the common "static phase converters", which are each for a specific narrow horsepower range, because the capacitor used for starting the motor has to be matched to the horsepower of the motor for fairly efficient starting.

That is indeed where this now belongs.

Enjoy, DoN.

I guess I do not understand the requirement. The device to use is a inverter. Inverters are VFDs without the variable bit and they are less expensive. Inverters are found in many devices like UPSs. They are driven by a DC supply, which can be provided by multiple sources including rectifiers. They can be found for almost any input source with outputs all over the place at any frequency and they are designed to be a power source for multiple machines. Years ago the solid state inverters were expensive and failure prone. Today they are inexpensive,sinusoidal and reliable with PFs better than .95. Just Google Inverters and see. Steve