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    Default One VFD for more than one machine...

    Long story short, I am moving overseas and taking my equipment with me. I've been using my RPC to power a panel that is wired to all of my equipment. As it turns out, that isn't a viable option due to the starting surge I have when I start it, so I am looking at a short term solution.

    So my question, and I can't find any information on it and I'm not experienced in VFDs at all, can you use one VFD to power one machine, unplug it and then plug in another and run that machine off of it also? I would of course use the VFD to start and stop them, but the part I'm confused about is, they say each VFD has to be programmed individually. Also, if I do have to reprogram it each time, do they make a VFD that has a memory built in for each different machine?

    Thank you in advance.

    P.S. I am going to a 50hz country and all of my machines are 50/60 except my radial arm saw.

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    Quote Originally Posted by michael.kitko View Post
    Long story short, I am moving overseas and taking my equipment with me. I've been using my RPC to power a panel that is wired to all of my equipment. As it turns out, that isn't a viable option due to the starting surge I have when I start it, so I am looking at a short term solution.

    So my question, and I can't find any information on it and I'm not experienced in VFDs at all, can you use one VFD to power one machine, unplug it and then plug in another and run that machine off of it also? I would of course use the VFD to start and stop them, but the part I'm confused about is, they say each VFD has to be programmed individually. Also, if I do have to reprogram it each time, do they make a VFD that has a memory built in for each different machine?

    Thank you in advance.

    P.S. I am going to a 50hz country and all of my machines are 50/60 except my radial arm saw.

    Sent from my S61 using Tapatalk
    Your radial-arm saw probably won't much give a damn. Modern motors for global markets are often engineered for 55 Hz anyway. RPM does the usual.

    There have always been "some" VFD that could store two or more sets of motor parameters. Some few were even common and used a plug-in NVRAM. Most "modern" ones have space in the NVRAM. Most expect a bulk download of externally stored parameters over a data cable or optical link anyway. Faster to set them up when used in a major industry than screwing with a keypad, one after another, after another, but you can do it from a laptop or "brick", even for a onesie.

    RTFM. It may be an option card needed. It may be an already built-in feature to store at least two.

    "Usually.." two - even three - simpler, CHEAPER mass-market VFD will cost less, overall, than one more complex one with external cutover goods & associated hassle.

    At 3 and more loads, if not already at TWO.. an RPC is usually cheaper yet.

    Care to share which country... AND city,... some among us "get around" - or did do - probably already know the utility mains environment you can expect to have to deal with.
    Last edited by thermite; 10-25-2021 at 12:02 AM.

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    I'm moving to Pontefract UK. We own a house over there and I'm pretty sure it's an old 50amp service to the house. This is just temporary as I am intending on opening a shop over in Castleford area.

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    Quote Originally Posted by michael.kitko View Post
    I'm moving to Pontefract UK. We own a house over there and I'm pretty sure it's an old 50amp service to the house. This is just temporary as I am intending on opening a shop over in Castleford area.

    Sent from my S61 using Tapatalk
    Disclosure: Dual National. US-UK. C&W retiree. Deep roots.

    No fear. Small-town West Riding is sorta like Canada, 1950 as to electricals.

    Ballsy Connecticut Yankees off to King Arthur's land..
    Y'all don't do things half-way, do yah?

    Besides.. anything as don't run proper-like will probably get nicked, sooner, if not later..

    Castleford voted one of the worst places to live in the UK | Pontefract and Castleford Express


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    Quote Originally Posted by thermite View Post

    Y'all don't do things half-way, do yah?

    Besides.. anything as don't run proper-like will probably get nicked, sooner, if not later...

    I had to laugh at the nicked comment. I've actually said that as a comment to my wife when we talked about going versus not going.

    What do you mean by doing things halfway? You referring to Canadians?

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    Quote Originally Posted by michael.kitko View Post
    I had to laugh at the nicked comment. I've actually said that as a comment to my wife when we talked about going versus not going.

    Sent from my S61 using Tapatalk
    "Petty crime" or so some thinkle PEEP it is "petty" .. might well class as Blighty's worst and most universal curse, actually.

    I include physical violence against the less-able as well pernicious theft.. but hafta laugh about one incident.

    My late, former next higher at C&W retired to his native Penzance. At six foot five and solidly built, he had always attracted the odd wannabee bully trying to PROVE summick, but now after a quad bypass, back problems and Old Age in general had grown more diplomatic than the Kernow average.

    Snailing back from the ordinary, wee hours, up Market Jew Street, he is accosted by a MORE inebriated hooligan who draws back for a roundhouse swing.

    "I wouldn't do that, if I were you!"

    And Pat doesn't even flinch as the fool shatters several bones in his hand on one of Penzance's characteristic landmarks:

    The stout, black, not at all obvious on the dark, cast-iron lamp post Pat is standing directly back of in black clothing!

    That lamp post just didn't give damn.

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    Short answer to the original question, for the most part a VFD is not a plug and play power source that can be used for different machines. In some cases, if the VFD is sufficiently oversized, it might be able to be used in this application but will not play nice with transformers and electronics, as it is PWM three phase and not true 3 phase. In most cases they are directly wired to the motor, no contactors, overload relays, etc. between the VFD output and the motor. They require low level programmed inputs to carry out their run functions, these and the motor specs. will vary between machines. So not plug and play. It is true that some VFD's have may have 2 sets of motor parameters, but the cost of the switch gear/wiring between machines and the proper inter-locks and different controls make it impractical vs. the cost of individual VFD's for smaller motor applications. Other option would be a Phase Perfect which does generate pretty close to sinusoidal output of an additional phase for 3 phase and can power multiple machines at once or individual within its rated load rating. There have been a number of threads as to use them in the UK, since it only generates a single phase. Best to speak to them if it is something you want to pursue and it fits your budget.
    Using a US manufactured digital phase conveter in the UK | Physics Forums
    Phase Perfect

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    There are many folks who actually do that.

    It clearly helps if the motors are similar. And if you run in plain V/Hz mode, so no special calculations and measuring of the motor by the VFD is needed.

    Unplug one machine, and plug in the next. that's basically what they do.

    It may not be perfect, or ideal, but it does work....

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    ^^^ What JST says for the cheapest solution. Don't bother buying the VFD until you get over here, they are readily available. If shipping cost isn't a problem (I guess not, compared with the cost of shipping the machine tools and houshold goods) then the starting surge of the rotary converter can be vastly reduced by using a pony motor to bring it up to speed before powering it on.

    Rotary converters are readily available over here as well.

    I currently run my workshop from a 415 TECO VFD that was modified by the supplier so that the internal supply acts as a voltage doubler and allows it to produce 415V three phase from our 240V single phase. The VFD is wired to all of the machines and once it's turned on, I run the machines exactly as if they were fed from the utility's 3 phase supply.

    That brings a different question:- Are your machines all 220V three phase? If they are, then an appropriate 240V VFD will be able to produce 220V 60Hz three phase from the 240V 50Hz single phase supply with no modification at all.

    Mark
    In Rugby, Warwickshire.

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    One of the general rules with VFD's, is no switches or controls between the VFD and motor, is my understanding.
    I've used a VFD for more than one machine, but only one at a time, sized for biggest.
    It is easy to put some sort of plug and receptacle (socket) in for the 3 phase motor cable, to allow change from machine to machine.
    But more difficult for the control wiring. In the past I've wired a simple low voltage receptacle to the VFD control circuit, then ran a lightweight control wire from each machine to this socket, thereby being able to control the VFD from the machine.
    Programming has never been an issue for me. The only functions I setup within the VFD are:
    - allow external control to switch VFD on/off.
    - starting ramp (how quickly motor starts up, maybe important for a flywheel)
    - braking resistor operation, to slow machine quickly - lathe spindle for example.
    Once set, these parameters don't really need to change machine to machine; just a compromise.
    VFD's are great !!!

    However, I've just got a heavy Bridgeport style mile (Supermax YC-2VAS) with three 3ph motors on it: 5 hp spindle, 2 hp X/Y feed, 1 hp knee feed.
    I'm thinking I need 3 inverters. If someone can convince me I only need one, I'm very interested to learn !

    Kinda similar question to OP, so hopefully not a thread hike.
    Thanks,
    Bob

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    Hey JST. I was looking into the same kinda thing. I understand a bit out vfds and rotary phase converters and such, and the option for use on multiple pieces of equipment was presented to me from a very smart electrician at work. He was mentioning that you run VFD with 230 VAC single phase input and 230 VAC 3 phase out put and then place a 3phase transformer that goes 230 VAC 3ph to 575 VAC 3 phase between the VFD and the motor. VFD still has to be rated for higher HP rating, so perhaps 7.5-10hp rating for a 5hp motor You have a time delay on the VFD for when you turn on the machinery equipment and you are basically just using the VFD as a phase converter set to 60hz, as all the other motors will be 60hz. I might be wrong but he said the smaller VFD's like below 10hp I believe are good for doing this. Then you can have multiple machines hooked up at once (not necessarily running all at the same time however, since the power draw might be too much). This also allows you to use your factory controls on the lathe or whatever that piece of equipment is.

    Does this work?

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    sorry if this is hijacking the thread.

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    [QUOTE=michael.kitko;3830035... starting surge I have when I start it, so I am looking at a short term solution.
    ...[/QUOTE]

    It is possible to build a rotary converter with minimal start surge.

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    Quote Originally Posted by Overland View Post
    One of the general rules with VFD's, is no switches or controls between the VFD and motor, is my understanding.
    There's actually no harm to even a finicky VFD, so long as they are not used to switch power while the power is actually active.

    IOW.. you could use a box of relays and contactors to replace the plugs and sockets.

    FIRST.. "configure" the array as wanted. Rotary switch. Row of toggles. Wotever.

    THEN bring the VFD to life.
    Run the machine(s)
    Power-down the VFD.

    THEN alter the matrix..

    ...bring the VFD alive. Run the next machine.

    Page Two:

    Enough folks - or accidents - have hammered enough VFD, that most makers have now built-in protection so they do NOT easily suicide if switched, encounter a broken wire ... or other accidental rudeness such as nearby thunderstorms, on their output.

    IOW, they are actually not all that fragile.

    Many never were.

    Designers expect rude environments. Its a major part of what they paid us for!

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    Quote Originally Posted by thermite View Post
    ............................

    Designers expect rude environments. Its a major part of what they paid us for!
    At least they SHOULD. Sometimes the bean counters don't agree.

    I've designed several VFDs that were INTENDED to have the load simply switched on and off instead of using the VFD slow start.

    You know what was different? Nothing, except that the IGBTs had to be able to stand the load motor being switched on at full voltage, which causes a large current surge.

    NO special protection for turning the motor off. The IGBTs with built-in diodes already handle the current being shut off tens of thousands of times per second....

    That said, some makers actually say not to do it. Since I don't know their reasons, I suggest going with what they say, even though engineering-wise, there are very limited reasons for that restriction.

    Some specifically allow it. If you really don't want to modify the machine, you can use theirs. But if you DO want to simply turn the machine on and off while on the VFD, you will need to get a VFD rated to handle the start current surge.

    Many VFDs have 150% short term current allowed, some have 200% allowed for maybe 2 seconds, which should start almost any motor that is going to start. You can use that overload capability in sizing the VFD. Just don't cut it too close on ratings, and be aware that ratings may change with temperature (they go DOWN). I like at least 25% "cushion", or margin, over the probable motor current, if possible.

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    Quote Originally Posted by JST View Post
    At least they SHOULD. Sometimes the bean counters don't agree.

    I've designed several VFDs that were INTENDED to have the load simply switched on and off instead of using the VFD slow start.

    You know what was different? Nothing, except that the IGBTs had to be able to stand the load motor being switched on at full voltage, which causes a large current surge.

    NO special protection for turning the motor off. The IGBTs with built-in diodes already handle the current being shut off tens of thousands of times per second....

    That said, some makers actually say not to do it. Since I don't know their reasons, I suggest going with what they say, even though engineering-wise, there are very limited reasons for that restriction.

    Some specifically allow it. If you really don't want to modify the machine, you can use theirs. But if you DO want to simply turn the machine on and off while on the VFD, you will need to get a VFD rated to handle the start current surge.

    Many VFDs have 150% short term current allowed, some have 200% allowed for maybe 2 seconds, which should start almost any motor that is going to start. You can use that overload capability in sizing the VFD. Just don't cut it too close on ratings, and be aware that ratings may change with temperature (they go DOWN). I like at least 25% "cushion", or margin, over the probable motor current, if possible.
    My experience, exiting "hollow state" for dawn of the transistor age, onward, it was always the CONTROL circuitry that was uber-fragile.

    Confuse the controls the wrong way? They can destroy the pass-elements FOR you!



    Early digital logic tribes were horribly susceptible to confusion from any fast-rise transient, and power-handling goods adjacent produced *plenty*, plus carried-in more-yet from line and load as "antenna farms'.

    Later goods were/are more tolerant, inherently. Even the early-days migration RTL, DTL, DCL, TTL to CMOS was a big improvement. Meanwhile, designers had learnt to better armour their entire PCB's, PSU's, improve ground planes.. protected cables and conductive routes in general, better buffer their control I/O, etc. etc. add noise-immunium.

    Can't make 'em "bulletproof" and still price affordably, "bean counter" or no.
    But they aren't TOO damned fragile.

    There is one if not two built-in VFD in each of:

    - my Panasonic Inverter Microwaves,
    - both laundry room worker-bees, Whirlpool Cabrio, GE Profile
    - LG "inverter linear" fridge/freezer,
    - "dual inverter" LG air-con..

    Just no VFD in my shop!

    No need.

    Mechanical variators or DC drives, rather. [1]

    Just the way my particular choice of Old Iron was built.

    [1] Plus rotary-power clean 3-Phase Wye off the gen set, a 10 HP Phase-Perfect, and "dial an idler" 3 HP to 20 + HP RPC via ... Delta to Wye drive isolation transformer for reasonably-safe "five wire" service.

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    so would my question above work then without much trouble?

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    Quote Originally Posted by thermite View Post
    My experience, exiting "hollow state" for dawn of the transistor age, onward, it was always the CONTROL circuitry that was uber-fragile.

    Confuse the controls the wrong way? They can destroy the pass-elements FOR you!



    Early digital logic tribes were horribly susceptible to confusion from any fast-rise transient, and power-handling goods adjacent produced *plenty*, plus carried-in more-yet from line and load as "antenna farms'.

    ...................
    That has not been a problem with newer devices. The early ones barely worked to begin with, using old-style straight bipolar transistors, which had lots of problems when used at the high voltages needed in VFDs.

    The issue is, for any decently and competently designed VFD, just the start surge if you intend to run a shop of standard machines and turn on via their switches.

    For what the OP is suggesting, there is no issue. He's just going to use different motors with the one VFD. And use it As a VFD, not just a 3 phase converter.

    That works.

    The one downside is that the VFD has to have the current limits set for the biggest motor, which means the smaller ones are not as well protected. That problem may exist when using "wall power as well.

    OK, one other issue is that the machine controls should not be used, because the VFD cannot start the machines at full voltage. So they may need modification.

    If you start via the VFD, and can avoid having your muscle memory making you hit the machine switches, it's fine. Otherwise you may find it less trouble to bypass the start stop on the machine.

    A rotary converter is a no-modification option, assuming all machines are good with 50 Hz.

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    Quote Originally Posted by JST View Post
    That has not been a problem with newer devices. The early ones barely worked to begin with, using old-style straight bipolar transistors, which had lots of problems when used at the high voltages needed in VFDs.

    The issue is, for any decently and competently designed VFD, just the start surge if you intend to run a shop of standard machines and turn on via their switches.

    For what the OP is suggesting, there is no issue. He's just going to use different motors with the one VFD. And use it As a VFD, not just a 3 phase converter.

    That works.

    The one downside is that the VFD has to have the current limits set for the biggest motor, which means the smaller ones are not as well protected. That problem may exist when using "wall power as well.

    OK, one other issue is that the machine controls should not be used, because the VFD cannot start the machines at full voltage. So they may need modification.

    If you start via the VFD, and can avoid having your muscle memory making you hit the machine switches, it's fine. Otherwise you may find it less trouble to bypass the start stop on the machine.

    A rotary converter is a no-modification option, assuming all machines are good with 50 Hz.
    Wellll. there is another thing one could do.. Skosh of waste to it, but rugged.

    Hybrid rig.

    Fat VFD running an idler at "n" Hz, anyone?

    I suspect the output side would be as flexible as an RPC, given the VFD would have substantial buffering?

    Look at the mass of 'non-rotating", but nonetheless seriously inductive Iron and Copper housed within a Phase-Perfect.

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    Quote Originally Posted by Mark Rand View Post
    That brings a different question:- Are your machines all 220V three phase? If they are, then an appropriate 240V VFD will be able to produce 220V 60Hz three phase from the 240V 50Hz single phase supply with no modification at all.

    Mark
    In Rugby, Warwickshire.
    Yes they are, except for the radial arm saw. I specifically went in search of 50/60 hz tooling, because my wife and I knew this day was coming for some time. The only tool I had to let go was a small belt sander and one of my angle grinders.

    Thank you for all the advice. I will take everyone's advice and set up an RPC and maybe one VFD for the saw.

    I did always wonder about that above, why can't you just set up a VFD to run a big motor and use that as an idler, like an RPC, to allow load switching on and off. I can't imagine it's any more different than using a horizontal mill and letting it get to full load after starting it on a VFD.

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