VFD Units and motor combo.
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  1. #1
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    Default VFD Units and motor combo.

    Hello! I have a 10" South Bend that i recently aquired, I LOVE it, it is the truest piece of machine shop equipment i own, it was taken care of meticulously by a gunsmith until i got it.
    but
    the motor has had it.

    was looking at this set up:
    http://dealerselectric.com/item.asp?PID=24792

    it is a matched system and its under 200 dollars.

    am I missing something? or is it really this easy? not counting motor mounting of course.

    any input would be amazing as there is so much incomplete info on setting up a VFD.

    thank you and thank you all for being here.

    dave

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    You will want to look for a 1700RPM motor or below if you want to run it on a VFD. Otherwise you won't get peak torque (1hp). In fact you would be operating at around 0.5hp if you ran that particular motor because it would only run to about 1700RPM's max speed at 30hz in your configuration.

    VFD's when driving induction motors provide constant torque to the rated speed and above that provide constant power (diminishing torque).

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    Quote Originally Posted by xplodee View Post

    VFD's when driving induction motors provide constant torque to the rated speed and above that provide constant power (diminishing torque).
    Not so if you have a dual voltage motor and have the high voltage as your incomming voltage Then connect the motor for the low voltage Then you have full torque up to about 80 Herz Here in Europe at least with a 400 volts net and a 240/400volts motor Most modern VFD can handle that AFAIN

    peter from Holland

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    You want a 1700ish RPM motor, and you want to be mindful of the shaft size on your current motor. If they are not the same, you will need a new pulley. Unfortunately, some of the older motor frame's shaft sizes are not used in current frames, so that might be unavoidable.

    allan

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    Wiring a VFD to your lathe is truly no more or no less difficult than wiring up a drum switch or 3-wire stop/start station. Especially dirt-simple Teco drives. I have a hard time endorsing that particular brand, but for home shop use you can't really go wrong at that price. I'd step up to a better brand if this is how you make your living, or else have a spare on the shelf. As others have rightly pointed out, that motor in the "package" might not be the best for your application. Buy their 100-dollar VFD and a used 3-phase motor of your choice locally to get your feet wet. Myself, I don't worry as much about mounting foot dimensions and shaft sizes, for once you've decided to go VFD you're no longer doing a "historically accurate" resto. Bore & broach or bush the pulley as necessary; drill mounting plate or make an adapter plate as necessary. Not such a big deal. For that money, it's cheap tuition to the VFD self-education class.

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    Chopper Daves as in Dave Freston? I hear the name frequently in the chopper world.

    I recently setup a VFD on my 9a, wired the 3 phase motor it came with into a Automation Direct GS2 and then cut up a 25ft extension cord to run the power to where my 220 outlet was. working great so far. Cost about $130 on ebay for the VFD plus whatever used motor you can find.

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    Yup. Jay. Same one. It's all lies!
    Yeah. I have it pretty much figured out. I'll make a post about it.

    Now if I could do the same thing to my Sebastian 20" lathe to double its speed THAT would be amazing. But I'm pretty sure it would launch into orbit at that speed.

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    I will admit that my experience in this area is limited, but I think that if you are going from three phase to three phase this VFD will work out. If you are going from single phase to three phase then the VFD needs to be rated for about 1.5 times the rating of the motor to be driven. Someone with more knowledge should probably chime in here.

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    No need to worry about "uprating" the VFD. If it's for single-phase to 3-phase conversion, the VFD is rated for the maximum HP 3-phase motor it will run. Getting one a little bit larger than the HP rating of the motor you're going to use won't hurt anything but it really isn't necessary since the drives all have some ability to handle overloads for short periods of time.

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    My understanding is that using single phase makes the input amperage too high for some VFDs when you drive the largest rated HP. That may or may not be the case here.

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    I used a 1140 motor because of the fan, it will stay cool at low speeds and over speeding the motor doesn't hurt a thing. Slow a 3400 down and it don't have enough cooling and it will over heat…… jim

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