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Thread: VFD for 4kw shaper and 2spd feeder

  1. #1
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    VFD for 4kw shaper and 2spd feeder

    I'm wondering if it makes sense to go with two vfd's to run my shaper (5.5hp/4kw 13.8 FLA) and 1hp feeder. I had wanted to power the feeder with a vfd either way to get variable speed.

    What are the chances I can successfully use a 12 amp vfd on a 13.8 amp shaper? If it was a ts or jointer I don't think it would be an issue but hogging out hundreds of feet of moulding makes me pause and think Id need the larger vfd.

    The other issue I'm concerned with is the 2 speed motor on the power feeder. I would think I'd use the low speed winding and just run the vfd up to 120hz to replicate the high speed?

  2. #2
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    Hi Jared, I would run the shaper with the VFD you have.

    The feeder I would run from a FD yet I would keep the 2 speed switch. No point running the motor at 200% speed when you could use the switch...Rod.

  3. #3
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    I have a VFD running the two speed motor on my drill press, no issues. You just can't change motor speeds when the motor is running but it has no issues if you play by the rules. Really, who changes speeds on the run anyway?

  4. #4
    Larry you cant change the RPM as its running? IM sure I saw one with a digital RPM readout and he was taking the speed and down just the same as you would change and dial in speed on a power tool that has vari speed.

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    Quote Originally Posted by Larry Edgerton View Post
    I have a VFD running the two speed motor on my drill press, no issues. You just can't change motor speeds when the motor is running but it has no issues if you play by the rules. Really, who changes speeds on the run anyway?
    I was under the impression I had to cut power to the vfd to switch down stream, or use one capable of being programmed to control both windings.

  6. #6
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    Quote Originally Posted by Warren Lake View Post
    Larry you cant change the RPM as its running? IM sure I saw one with a digital RPM readout and he was taking the speed and down just the same as you would change and dial in speed on a power tool that has vari speed.
    Thats my exact goal with using the vfd with a remote pot on the feeder, and hopefully save myself from buying a dc40

  7. #7
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    You can not switch the motor from high to low while the vfd is supplying power. You have to turn off the vfd, change the high/low switch then power up the vfd. Of course once the motor is running you can vary the VFD frequency to adjust motor speed.
    120 Hz is too high for most motors, especially high rpm ones. You would be running that motor over 7,000 rpm. It is not balanced well enough for that. That is probably too fast for the bearings as well. Recommend 40-80 Hertz range as safe. I am not sure the motor fan will work correctly at 7000 rpm.
    Bill D.
    Last edited by Bill Dufour; 08-21-2018 at 10:57 PM.

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    Quote Originally Posted by Bill Dufour View Post
    You can not switch the motor from high to low while the vfd is supplying power. You have to turn off the vfd, change the high/low switch then power up the vfd. Of course once the motor is running you can vary the VFD frequency to adjust motor speed.
    120 Hz is too high for most motors, especially high rpm ones. You would be running that motor over 7,000 rpm. It is not balanced well enough for that. That is probably too fast for the bearings as well. Recommend 40-80 Hertz range as safe. I am not sure the motor fan will work correctly at 7000 rpm.
    Bill D.
    Wouldn't running the motor (on the low speed winding) at 120hz be the same 3600ish RPM as running it on the high speed winding at 60hz.

  9. #9
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    The problem with running a motor at 120hz is the ratio of volts to hz is no longer maintained. Better to run at 30 hz for low and 60 hz for high. You want torque for a feeder. Dave

  10. #10
    On my air compressor it was originally a 3450 rpm motor. I replace the motor with a 1740 rpm motor. I kept the sheave the same size on the motor. So at 60 Hz the pump is doing half the amount of work. I run the air compressor sometimes for quick filling at 140 Hz, and sometimes I run it at 30 Hz, sometimes I run it at 60 Hz, and sometimes I run it at 90 Hz.

    I’ve set up three different programs 4 recovery air speeds, with four different pressure sensors. Most of the time during the day I let it recover at full tilt (140 Hz).

    The air compressor is plugged almost 24/7(except for when I’m using the Lathe. Shared outlet)

  11. #11
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    Quote Originally Posted by Warren Lake View Post
    Larry you cant change the RPM as its running? IM sure I saw one with a digital RPM readout and he was taking the speed and down just the same as you would change and dial in speed on a power tool that has vari speed.
    Warren, you can change speeds with the VFD within the motor speed that is selected, but can not change from one motor range to the other without shutting off the VFD first. There would be a contact/no contact/contact moment that would damage the VFD as you switch motor ranges. Its really cool for some stuff, like Versatech plugs. I can get it down to such a low speed with the Reeves drive, low speed, and turning down the VFD I can cut large tapered plugs without melting in plastic.

    I just can't change motor speed range on the fly, no big deal to me. I see Bill covered this, and he probably makes more sense.

  12. #12
    I just wired up my feeder using a vfd feeding through the speed switch. I'll hit the stop button and then change the speed switch. I don't know what happens when it's switched under power, but I'm not gonna find out either. This set up is kinda neat because it gives you 4 ranges that you can vary the speed in. I have mine set up so I can go 20% over or under on hz.
    Last edited by Tim Einwalter; 08-24-2018 at 8:49 AM.

  13. #13
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    Quote Originally Posted by Tim Einwalter View Post
    I just wired up my feeder using a vfd feeding through the speed switch. You can change the speed switch when the motor is under power. I'll hit the stop button and then change the speed switch. I don't know what happens when it's switched under power, but I'm not gonna find out either. This set up is kinda neat because it gives you 4 ranges that you can vary the speed in. I have mine set up so I can go 20% over or under on hz.
    Thanks everyone. Ill plan on using the switch and keeping the hz between 30 and 60

    Now I just need to find a source for this older style drive assembly case first.
    20180822_213445.jpg
    Last edited by Jared Sankovich; 08-23-2018 at 6:20 PM.

  14. #14
    It looks a lot like the Delta/Comatic that I have. The difference are the screws that hold the covers on. You might end up having to convert the back aluminum part to a snap on style cover. Be forewarned; due the the tariff bs, lead times are measured in months.

  15. #15
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    Quote Originally Posted by Tim Einwalter View Post
    It looks a lot like the Delta/Comatic that I have. The difference are the screws that hold the covers on. You might end up having to convert the back aluminum part to a snap on style cover. Be forewarned; due the the tariff bs, lead times are measured in months.
    Its a co-matic. Who did you order from? all the parts I needed were in stock.

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