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Thread: VFD on Power Feeder

  1. #1

    VFD on Power Feeder

    Converting 3 phase machines with a VFD is nothing new, but is this typical on a power feeder? I just bought a 3 phase 1hp 4 wheel feeder, and id like to keep it if i can power it. I guess my only/primary concern is if its dumb to have the VFD several feet away from the machine its powering? As long as the cables are long enough, i should have the freedom of movement to swing and position the feeder.

  2. #2
    Join Date
    Feb 2011
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    Patrick, you can run the feeder from a vfd but you must pick a speed and leave the drum switch on and use only the vfd to start and stop the feeder. You would need a switch close to the machine but that could be accomplished. Involves some work but doable. Dave

  3. #3
    Join Date
    Dec 2006
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    It's a good way to run a feeder, as David indicated the feeder switch must be left in one position and the control of the feeder has to be via the VFD.

    If it were me, I would disconnect the selector switch on the feeder to prevent accidental operation of the switch.............Rod.

  4. #4
    I have one of mine running on a vfd and it's really handy for finding the sweet spot speed. I choose the mechanical gear on the feeder than leaves the motor running faster so the cooling fan is moving more air.

  5. #5
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    You don't want to break the connection between the VFD and motor. That could damage the VFD. I think some VFDs have connections for remote start / stop.


    John

  6. #6
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    Sep 2016
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    You could use the existing switch on the feeder to control the vfd. or you could mount a control box anywhere on the feeder arm etc. I would mount the vfd and any control switches all onto the feeder so it is easy to move the entire setup to another machine. Note that the control switches are low amp and low volt so they can be cheap and light weight to move around. Also there is no need to only have one control box. I have some machines, like my planer, with an extra off switch on the outfeed side.
    Bill D

  7. #7
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    Quote Originally Posted by John McClanahan View Post
    You don't want to break the connection between the VFD and motor. That could damage the VFD. I think some VFDs have connections for remote start / stop.


    John

    I guess I've been doing this wrong on my drill press, can someone explain how this hurts the VFD? About half the time I use the machine switch. Of course it won't soft start or brake when using the machine switch, but I don't see how it would be hurting the VFD. Been working for 8ish years now. My VFD has a provision for a remote switch, but I've never taken the time to mess with it.

  8. #8
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    2 speed motor? If so you still need to use the original drum switch and shut down the vfd when changing from high to low speed.

  9. #9
    Ok, so this is all kinda in line with what I was thinking. Pick a middle speed gearing on the feeder and leave it there, because the VFD will give me some ability to slow it down if the situation calls for it. It won’t be as nice as the dc40 I have, but it won’t be nearly as much either. I operate the VFD from jack with a remote switch already, and I planned on connecting that little switch to the feeder itself, but having the VFD bolted to the saw cabinet. Then again, it might be nice to buy a dc30 or 40 and just run it off 110. My panel is just about maxed out, and this feeder would need a new 220 breaker and line. All my other machines are on dedicated 40amp lines.

  10. #10
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    Sep 2016
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    Quote Originally Posted by Steve Rozmiarek View Post
    I guess I've been doing this wrong on my drill press, can someone explain how this hurts the VFD? About half the time I use the machine switch. Of course it won't soft start or brake when using the machine switch, but I don't see how it would be hurting the VFD. Been working for 8ish years now. My VFD has a provision for a remote switch, but I've never taken the time to mess with it.
    Turn off the switch and the VFD has enough capacitors and whatnot inside that it will continue to power the output line. It senses no rpm feedback so it increases the output as high as it can. No where for that power to go so it sort of finds any weakness in the vfd and blows it out there. And it is driving the motor as a rotary generator while doing this. A drill press has limited momentum of spinning mass so not much back feed power. If it was a big lathe with. a lot of spinning high speed mass it would probbaly have blown the vfd years ago.
    Kind of like running an engine on a test stand with no load. Just because it has no load does not mean it is safe to give it all the gas it can take. My FVD will stay lit and powered up for 45-10 seconds after I switch off the breaker supplying it. It stores enough energy, after power off, to spin my lathe several times around from a dead stop. that is probably more then 50 pounds of gears and chuck.
    Bill D.
    T

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