VFD with breaker on output...?
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  1. #1
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    Default VFD with breaker on output...?

    OK...I think I know where this will end up but I thought I'd ask anyway.

    Getting ready to connect up a VFD to my 'new' Whacheon lathe that uses a 7.5HP 3 phase motor. I like the idea of the VFD allowing me to run a 'large' motor on single phase 240V power, and the way it will ramp up the motor without full inrush. But, I don't like the way I will need to use the VFD controls to do the controlling....I'd rather use the switch that comes with the lathe.

    So....theoretically...what would happen if the VFD were turned 'on' with no load - then the motor switch was flipped 'on' which placed the motor load on the VFD? I think it wouldn't like it...but I'm wondering if anyone has tried it?

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    Not really a question of "trying it" so much as you would need to rate the VFD for the Locked Rotor Amps of the motor. Which would be rather massive for that motor.

    Why not wire the low voltage VFD control circuit into the lathe's existing switch you like?

    -Phil

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    Or if the OP doesn't want to mess with the machine controls, mount a separate control panel.

    Tom

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    We put a VFD on this same style lathe only on a Mori . . . and we let the VFD handle the controls from the original switches and brake. It works awesome and we would do it again in a heartbeat.

    If you have interest, I can see if we have prints available to guide your VFD install.

    VFD install on Mori MR2000 Lathe

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    Quote Originally Posted by GregSY View Post
    OK...I think I know where this will end up but I thought I'd ask anyway.

    Getting ready to connect up a VFD to my 'new' Whacheon lathe that uses a 7.5HP 3 phase motor. I like the idea of the VFD allowing me to run a 'large' motor on single phase 240V power, and the way it will ramp up the motor without full inrush. But, I don't like the way I will need to use the VFD controls to do the controlling....I'd rather use the switch that comes with the lathe.

    So....theoretically...what would happen if the VFD were turned 'on' with no load - then the motor switch was flipped 'on' which placed the motor load on the VFD? I think it wouldn't like it...but I'm wondering if anyone has tried it?
    Enough folk have blown-up VFD doing that, that many of the recent industrial models are even armoured-up to survive it! The expensive ones. Of course!



    Dirt-simpler to dig the VFD manual as to remotable controls and provide such.

    They are low-power, low voltage, can use compact switches. VERY compact.
    Speed pot as well. Low-wattage. Rotary OR linear-slider. I use the high-grade ones made for recording studio master control panels. Alps & Bournes.

    So if you do not want to dig into the machine-tool's control wiring and bring it out?

    Just position the new remotes to the VFD right in front of the old and abandon the old in-place. You only lose about an inch.

    .. For.. ta da ..later use when the machine is back in a 3-Phase-available environment. If-ever.

    It's only a LATHE.

    It never OWNED as many controls as some 5-Axis creature.

    How hard can that be?

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    Some/ many VFDs will fault if powered up unconnected to a motor.

    Toshiba Tosverts for sure, Siemens also.

    In which case, the question is "unpossible".

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    Is this with current VFDs? When did it happen?

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    Quote Originally Posted by Mark Rand View Post
    Is this with current VFDs? When did it happen?
    Prolly 20 years already more than a few - DC Drives a well- have a "commissioning" mode specifically meant to enable pre-setting such parameters as are wanted put in place before a live load is attached.

    And/or for a maker, integrator, or end-Luser firm using many to ship units pre-set to their specific needs as lower-skilled local hands "swap and forget" spares not meant to be messed with at point of use.

    Still there, I suspect. The default refusnik behaviour only a safety if the toolset provided is not taken advantage of.

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    Oops, I read 'fault' as 'fail'.

    The fault bit is normally a simple configuration change. Just like input phase failure (e.g. running a 3ph vfd on 1ph power) is.

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    Quote Originally Posted by thermite View Post
    ...
    And/or for a maker, integrator, or end-Luser firm using many to ship units pre-set to their specific needs as lower-skilled local hands "swap and forget" spares not meant to be messed with at point of use.
    .
    LIke whomever sold my my Hitachi drive, with manual. Manual insists user MUST set certain parameters. Drive is shipped with a
    reduced instruction set locked in there, preventing said setting operation. Took me a while leafing through the manual, into the third
    higher order parameter spaces, before I figured out what had to be done.

    They might have at least *mentioned* the page number and the parameter code.

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    Quote Originally Posted by jim rozen View Post
    LIke whomever sold my my Hitachi drive, with manual. Manual insists user MUST set certain parameters. Drive is shipped with a
    reduced instruction set locked in there, preventing said setting operation. Took me a while leafing through the manual, into the third
    higher order parameter spaces, before I figured out what had to be done.

    They might have at least *mentioned* the page number and the parameter code.
    LOL! No telling what some out-of-reach "genius" gets up to onct a de facto "general purpose computer" finds its way into the guts of ANY appliance.

    David S--- and I two separate continents, same HQ, were putting "Pee Cee's on the office staff's desks with stripped BIOS proms.

    Kept them focused on their JOB, not the mischief they could get up to with a new "toy" if it had no I/O handy to load the trash & risk they aimed at it..

    Whomever did yer VFD had a similar goal. Configure to do what THEY wanted to do, discourage change by deliberate crippling.

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    Smart idea is to do the factory reset before using any VFD.

    Usually it is explained in the manual, sometimes there is a special procedure to access it.

    And certain VFDs such as the "forbidden brand" are sold by some as standard units, but may actually have a special program that lacks many parameters that were not changeable in the particular application. Then you are screwed.

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    Thanks, good ideas.

    The VFD is a new WEG CFW700 and it has a detachable remote control.
    https://static.weg.net/medias/downlo...re-english.pdf


    But, perhaps I could use the original lathe's switch to turn on the VFD. It does have a series of terminals and I thin it allows for that. Then, I wonder if it also has the ability to handle both CCW and CW rotation 'signals'? I'll have to research that.

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    Quote Originally Posted by GregSY View Post
    Thanks, good ideas.

    The VFD is a new WEG CFW700 and it has a detachable remote control.
    https://static.weg.net/medias/downlo...re-english.pdf


    But, perhaps I could use the original lathe's switch to turn on the VFD. It does have a series of terminals and I thin it allows for that. Then, I wonder if it also has the ability to handle both CCW and CW rotation 'signals'? I'll have to research that.
    Yah. "Enable" or "RUN" function.

    What they actually do is part of your programming choice set.

    Depends on whether you program for that to also mean got-to some initial RPM in FWD or read an external potentiometer - presuming there IS one. You have options.

    The detachable panels - usually able to use a stock or made-up to fit telco/data RJ-45 flat cable of arbitrary length up to about ten feet or so, are better than NOTHING, but still have the tiny chicklet buttons, etc.

    By adding three wires for potentiometer, 2 or 3 each for ENABLE, RUN FWD/REV and a JOG.. better-yet "CREEP" if it can do that, you can select just about any size and appearance and placement of the switches and knobs desired.

    One of the features I've come to love with the Eurotherm/Parker-SSD DC Drives I've settled on is that ONE SINGLE potentiometer is ALL of:

    - OFF/BRAKE ..when centered

    - FWD, and to what RPM, rotated in one direction from center

    - REV, and to what RPM, rotated the other direction from center.

    And that how fast you move it either way determines how aggressively it accelerates or brakes as well.

    All with just one "handle" and 3 wires....

    Pity a lathe doesn't need a bucket-tilt, boom extend, gun-switch or bomb-release function.. I could adapt some GI joyce stick off a warbird, a games console, or a backhoe/trackhoe!


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    Quote Originally Posted by GregSY View Post
    But, perhaps I could use the original lathe's switch to turn on the VFD. It does have a series of terminals and I thin it allows for that. Then, I wonder if it also has the ability to handle both CCW and CW rotation 'signals'? I'll have to research that.
    You’re in the right track. Nearly all VFDs allow pretty significant remote operator (beyond just Fwd and rev) from the low voltage control circuit and in a customizable fashion. The manual should cover it pretty well. Good idea to read that manual cover to cover prior to getting started. There will likely be a lot you don’t need to touch, but good to know what it’s capable of.


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