VFD vendor?

It is tailor made for the application. W.W. Grainger also has some like it listed in their catalog. The price in the catalog is higher, but might be worth checking to see what price you can get one for. W. W. Grainger has various prices depending on who you are.

Dan

It depends on what you are looking for. The Teco unit has simple V/Hz control (basic method of speed control) as well as sensorless vector operation, which is a way of getting better speed control from a motor without having to have an encoder or other feedback device, and it relies on DC injection braking to stop the motor quickly if needed. The Automation Direct drive only has V/Hz speed control, but you can use DC injection braking, or you can connect a braking resistor to the drive for decelerating high inertial loads at a controlled rate without faulting the drive on DC bus overvoltage. Automation Direct also carries more options for the drive. I have used one of the GS2 drives before, and had no problems with it doing the job, but I think the one I used was a 3 horsepower 230 VAC unit that I connected to single phase.

I looked back at the original post, and it talked about replacing a single phase motor on a drill press with a three phase motor and using the drive to power the three phase motor, so I don't think you would need to worry about using sensorless vector control in this application, unless you needed all the torque you could get out of the motor at low speeds. I would think that either of the drives would do the job in this application just to power the 3 phase motor.

Sounds good, Dan.

Last time I was in Grainger, they refused to sell me a can of aerosol contact cleaner, citing some really hinky sounding requirement. Weirded me out, so I decided to send money elsewhere. I will tell my pal where he can find the best gear at the best price.

I appreciate your time.

--Winston

(...)

Thanks for the info, John. It inspires confidence to have another set of eyes double - checking the fine print. I think my pal will be pleased with the results.

I appreciate your time.

--Winston

[ ... ]

In my experience, the Mitsubishi VFDs will operate nicely with single phase input -- with the caveat that you should not expect to get the full rated horsepower out of them unless they specify single phase, but if you load them no more than 2/3 of full rated load, you should be fine.

You *might* need to wire one of the input lines into two of the input terminals (some come with a jumper for that purpose, in other cases you simply crimp on two terminals on a short piece of wire and add them in the appropriate place).

*That* is going to be tricky. Why do you *need* 115 VAC input? Your e-mail address suggests that you are in the US (near Chicago perhaps, though I'm not sure how wide spread bigbrother.net happens to be.)

In the US -- almost *all* homes have 230 VAC input to the home

-- with a grounded center tap, so you can get 115 VAC either side of the ground. Running from 230 VAC will halve the current draw and thus decrease the chance of nuisance trips of the breakers. (I rewired the single phase 1-1/2 HP motor on my lathe from 115 VAC to 230 VAC to eliminate those nuisance trips.) It is easy to get 230 VAC from the breaker box with a double breaker plugged in. You are likely to already have 230 VAC wired in if you have any of the following major appliances:

Electric hot water heater

Electric clothes drier

Electric kitchen stove.

The stove and the clothes dryer are likely to even be plugged in, while the hot water heater will be hard wired on its own breaker.

If you don't have an outlet for 230 VAC single phase somewhere around the house, it is likely to be easy to add. If you are setting up shop in the room where the breaker box is located, you can probably even do it yourself. Otherwise, pay an electrician.

Even if you have an ancient house with a fuse box instead of a breaker box, there should be provision for two or three 230 VAC loads, with double cartridge fuses in a plug-in carrier box. (But I would take this opportunity to upgrade to a proper breaker box anyway.

The only VFD which I have seen which accepts 115 VAC single phase input and produces 230 VAC output is limited to 1/8 HP. I would consider one designed for 1 HP or higher to be likely to be unreliable, simply because of the extra ripple current in a voltage doubler circuit

-- and the extra capacitors needed. Why pay a premium for something less reliable and harder to find when it is so easy to give the VFD 230 VAC single phase.

Enjoy, DoN.

It doesn't look bad.

I still don't see why you are locked into 115 VAC. That is the hard way to go for driving a 230 VAC motor.

Good Luck, DoN.

(...)

My bad. Iggy generously supplied the proper documentation showing this to be a 1 HP unit.

I will put that away for future reference. Thanks!

My pal had the drillpress running from a conveniently placed 115 VAC outlet. I want to give him a reasonably - priced three phase solution that won't require much (or any) house rewiring.

I'm in Silicon Valley, California. My address is munged to protect me from even more spam.

Thanks for the info. I rewired my vertical mill for 230 V and installed heavy wiring for my welder. The drill press is at a pal's house, though. When I discovered the Teco VFD, it appeared to be a good answer to the various requirements. At U$ 131.00, it is very reasonably priced for a name brand, too.

Thanks for your comments, DoN.

--Winston

(...)

My pal had the drill press running from a 15 A outlet. If I could come up with an answer that didn't require much effort on his part, he would be a happy camper.

I guessed that we were looking at say 1080 W into the VFD for a 3/4 H replacement motor. That's about 9 A. So, it's about 67% more current that his old motor required but he gains the advantage of fine speed control and faster stops, without house rewiring.

Teco has a good reputation, so I figured their 1 HP product should be able to power a 3/4 HP motor reliably.

It *is* a lot of current, but it's well within the capabilities of the existing wiring.

That's pretty much my reasoning.

Thanks!

--Winston

working for a

transformers on

A 1500+ foot

Not necessarily. There's this woinderful thing about some flammable gases, they have both a Lower Explosive Limit and an Upper.

If you are above the UEL - essentially 100% gas and 0% oxygen - no boom. It can't if there is no oxygen to burn.

Same thing happens withg the electric fuel pump in your gasoline tank.

100% gasoline and vapors, no Oxygen.

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As do I professionally.

Gunner

"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

(...)

That's one of those things one can understand from an intellectual viewpoint yet still get a chill down the spine.

Wah-Hawooo! There it goes again. :)

--Winston

Oh yeah, my first thought on that one was "Are they INSANE?!?!" too.

But after a while the rational side of the brain takes over.

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