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3 Phase Motor, Looking For Vfd Requirements

Discussion in 'Grinders' started by Bluefish, May 23, 2018.

  1. Bluefish

    Bluefish New Member

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    i happened across a baldor 2 Hp, 3 phase motor today. How do I go about looking for a VFD? What am I looking for? Will post a pic if it will let me. https://imgur.com/gallery/AggmE6P
     
  2. Griff

    Griff Active Member

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    https://www.amazon.com/KBAC-27D-Black-Drives-Nema-Inverter/dp/B007YA2YYE

    This seems to be a popular model Bluefish. Do some research though, but I think this one would work. And it actually ships to Canada, who'd a thunk-it lol! I think it needs a wiring kit and specified 110 or 240 when ordering the wire kit.

    I think Dan has experience with ordering from Amazon on a VFD.
     
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  3. ToddR

    ToddR Putterer, Tinkerer, Waster of Time Staff Member

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    Be wary of the "free shipping" on this VFD. I bought this exact one and I got dinged with a $70 customs fee when it was delivered COD. I ended up paying about $550 for this vfd when all was said and done. I mean, i couldn't find it any cheaper in Canada but, just be prepared for a little surprise when it shows up at your door. Also, you still need to wire it up so you'll still need the wire, spade connectors, a reverse switch (if you want one) etc.
     
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  4. Bluefish

    Bluefish New Member

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    would having reverse be a good option?
     
  5. Griff

    Griff Active Member

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    @ToddR
    Dinged is an understatement ordering from the states...my Paragon Oven is on its way...and it's $500 shipping, and god knows what $$$ waiting for me when it gets here!

    @Bluefish reverse is not a bad option, nice for sharpening I hear from some. The power on/off switch is nice on these too.
     
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  6. ToddR

    ToddR Putterer, Tinkerer, Waster of Time Staff Member

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    Yeah, i forgot about sharpening. I have 2 1x30's, a grinder with paper wheels and an assortment of sharpening jigs/stone i use for sharpening. I don't plan on using my new grinder for that. Maybe i should though? Get rid of all the other stuff.... (bite your tongue Todd... get rid of tools you don't need and rarely use!?!?!? What's the matter with you?)
     
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  7. Eric Fisher

    Eric Fisher Member

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    Have you confirmed the motor is suitable for VFD operation? Some are not. You should be able to do that on Baldor's website.

    What power supply do you have available? 1 phase, 3 phase? 110V, 230V?
     
  8. dancom

    dancom Dust Maker Best Shop Tool

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    That's a great motor. To get the most out of it you will want at 240 V 15 A single phase supply in your shop. Many VFD models seem to have a limit of 1.5 hp with 120 V supply.

    I have a bunch of 3 phase motors and have never had one wouldn't work on a VFD when connected to short motor leads. The primary issues are harmonic heating and insulation failure due to transients (voltage spikes). As you are running the motor at the lower of the two voltages 230V vs. 460 V the dielectric strength of the windings will have to be 1920 VAC (2 times rated plus 1000 V) to meet UL/CSA standards. Keep your motor leads short and your speeds up and you'll be fine. One caveat here...some VFDs do not like high efficiency motors. This was the case with some versions of the KB electronics VFDs. Apparently a firmware fix corrected this.

    I got my KBAC-27D from Amazon.com. No shipping surprises, duties, tax and shipping were all in the cost at checkout. This was the VFD and vendor I bought from: https://amzn.to/2xgTTRN

    This is the latest three phase motor in the stable (the first picture was as it was posted on Kijiji last month). Baldor four pole 2 hp. $40

    [​IMG]
    Touched up the paint in True Blue.
    [​IMG]

    Dan
     
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  9. Griff

    Griff Active Member

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    @dancom Dan did the unit from Amazon come with a wiring kit? I have seen on the Reeder Products website that when you order their grinder with a 2HP Leeson motor and KBAC27 (no D on the end) that you have to purchase a wiring kit separately from them and specify if you are running 110V or 240v. The kit is a 4ft cable for motor to drive, and then an 8ft cable for drive to mains. 110v kit is $50 US and 240v is $40.00 US.
     
  10. Bluefish

    Bluefish New Member

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    I've got 230 in my wood shop, have no plugs for it yet but that is coming. think I need to upgrade my panel in there first then add a few outlets. Want to run 230 to my metal shop soon as it has a cement floor but will make do with what I can get by with for now. Need an outlet for my heat treat oven anyway, might as well add another for this grinder. Now just need to pick a design and get my hands of some steel plate.
     
  11. dancom

    dancom Dust Maker Best Shop Tool

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    I did not order the optional kits. What I did do was this...

    Line switch install:
    http://dcknives.blogspot.ca/p/kbac-vfd-line-switchinstallation.html

    Forward/Reverse Switch Install
    http://dcknives.blogspot.ca/p/kbac-forward-reverse-switch-installation.html

    For power wiring I went to HomeDepot and grabbed some SJOOW cable by the metre and some strain reliefs from the electrical department. I went with a 4 metre supply cord (3C/12 AWG) and a 1 metre motor cord (4C/14 AWG). The strain reliefs were QTY 2 of 3/4" and 1 of the 1/2" size. I think all up the cord was around $30.

    Dan
     
    Last edited: May 28, 2018
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  12. ToddR

    ToddR Putterer, Tinkerer, Waster of Time Staff Member

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    Does anybody else think Dan sounds a bit like Scotty when he talks about motors? : ) "Harmonic heating and insulation failure due to transients" sounds a lot like "the entire dilithium crystal converter assembly is fused" to me. But really, electrical theory on the level he knows it is science fiction to me anyway.
     
  13. dancom

    dancom Dust Maker Best Shop Tool

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    Captain,

    I am givin' it all she's got! I can't give no more!

    Actually feeling more like Bill Nye today.

    When you run a VFD you may hear a whining sound...it sounds like a whistling in the motor. This is a result of the high speed switching of transistors that is going on inside the VFD when the VFD is making the three phases. Typically this switching is between 2 kHz and 16 kHz and that is the part you hear. BTW, some of us can't hear 16 kHz. As we age our high frequency hearing degrades. This could also be logarithmically related to the number of heavy metal concerts we've attended. LOL

    In a very simple form, if you can imagine a long rope attached to a door knob. Pull the rope taut and give it a whip and you setup a wave that moves down the rope towards the door knob. When the wave hits the door knob, a small amount of the wave's energy heads back towards you. If you time it just right you can use that returning wave to boost your next wave going towards the door knob. If your timing is impeccable and repeat this over and over you can create waves that go back and forth in resonance, where the timing and the length of rope work together. The bad part is the reflected waves can seriously increase the your supplied waves. If the waves in the rope represent voltage, the door knob represents a motor and the rope represents your motor cable, the voltage can increase beyond the voltage rating of motor and cause insulation failure in the cable or motor. That is the wire's insulation or varnish on the windings gets a hole in it and it leaks like a garden hose with a hole in it. That is a bad thing. We can however control two factors: the length of the motor cable and the switching frequency also known as the 'carrier frequency'. The carrier frequency is controlled by a parameter in most industrial AC VFDs. This is not the case in the KBAC series where the carrier frequency is fixed at 16 kHz. Keeping the motor cable short is the best way to prevent "insulation failures due to transients."

    Harmonic heating in the motor can be an issue as well as heating caused by running the motor slowly for long periods of time. Both of these conditions are improved by running the motor and thus its cooling fan faster. Remember affinity laws from high school? The idea is that running a fan even a little slower significantly reduces the volume of air it is moving. The solution is to run the motor at or near rated speed "most" of the time and you are golden.

    With this in mind, you can run almost any 3 phase motor on a VFD.

    At my work we design systems where very large motors (up to 1.5 MW) are placed at the end cables that can be 10 km long. Each case in unique, but you can imagine the waves that are bouncing back and forth on that "rope." In order to allow these kinds of systems operate for more than a few minutes we add passive filtering (electrical kind of filters like a treble knob on an amplifier) that block the carrier frequencies and higher harmonics from reaching the motor. These filters are available for small motors too, however the above mentioned DIY approach works well for garage warriors like us.


    And now the tag line...

    Dan Comeau is the Assistant General Manager at SUBCOE, Submersible Consulting & Engineering a Canadian supplier of specialised Variable Frequency Drives for the global oil and gas market.
     
    Last edited: May 29, 2018
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  14. ToddR

    ToddR Putterer, Tinkerer, Waster of Time Staff Member

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    Great explanation. Mechanical resonance is something I'm familiar with. Never heard it used to explain electrical theory before, nicely done. Assistant Manager at a place that makes VFD's? Now i know how you can afford to put a vfd on everything you make (grinder, sander, toothbrush, blender, etc. : )
     
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  15. Griff

    Griff Active Member

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    @dancom Dan are you still running the Ironhorse motor you got from automotion direct with the KBAC-27?
     
  16. dancom

    dancom Dust Maker Best Shop Tool

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    Yes. The KBAC-27D is on my 9" disc grinder. It works sweet. History wise, it's new to the stable as I bought it early this year. It's my second Ironhorse motor. The first Ironhorse I bought for my Sayber OSG about a year ago. It's driven by an inexpensive HuanYang 2.2 kW VFD and it has been run over 220 hours since June last year without issue. No complaints. Solid motors for the price.

    Dan
     
  17. Griff

    Griff Active Member

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    Thank you Dan. Besides a new grinder I am looking to upgrade my current grinder's motor (1.5hp single phase) to a three phase 2hp with a vfd. Having learned to grind free hand on a motor running full speed I am curious to see how much more control I will have playing around with a vfd.
     
  18. ToddR

    ToddR Putterer, Tinkerer, Waster of Time Staff Member

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    Hey Griff. I have to ask two things - 1. is grinding free hand a time saver for you or give you more control? 2. how did you teach yourself? Are there any tips/tricks or is it just grind, check, grind, check - oops - try again - until you get it? I have tried in a few sessions to grind freehand and came nowhere close to anything productive. I don't seem to have the coordination or something. It is something i figure i should learn because - well - I dunno why i just sort of feel like i should.
     
  19. Griff

    Griff Active Member

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    Todd, YouTube videos, I am a visual learner...you can talk to me until you're blue in the face and I may or may not get it, but show me once and I am golden.

    I should state I meant freehand hollow grinding. I have yet to master flat/convex grinding, and I will no doubt use a jig to flat grind to a certain angle/height and then free hand in the convex.

    And here is why...My grinder is an AMK 72, and as much as I love the ingenuity of this grinder that lets you flip from flat platen to 10" contact wheel without changing a tool arm, there is one flaw. On the left hand side, so standing at the platen, your left hand draw as you pull the knife across is heavily restricted by the platen frame and the machine, so flat grinding / convex (especially getting to the plunge line and forget about having file guide it won't get near it!) was so difficult the machine forced me to learn hollow grinding first, and to date foremost, because the ten inch contact wheel sticks out from the frame and pulling the blade either side is unrestricted. Look I love my grinder, but I bought a new house, I finally have a garage/shop all to myself so as much as I love my AMK 72, I am going to get another grinder, probably the Reeder.

    Also to note Todd I cut my teeth, and spent a crap ton of money, and tossed several 01 blades in the garbage before I ever finally finished my first knife. I never got the bright idea to track down mild steel to practice on! You've got to keep at it if you want to do it, if you don't there's nothing wrong with using a jig, make knives the way you want to make them. What I am concerned about right now is having lost the feel for it as I am coming up on a year hiatus, my dads kitchen knife was the last knife I made and that was last August!:confused:

    Below are a couple of videos that Mike Ekim Knives made, they helped me a great deal learning to hollow grind. There's 4 parts, but here are the first two.



     
    Last edited: May 31, 2018
  20. dancom

    dancom Dust Maker Best Shop Tool

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    For learning, I find nothing beats doing. Once you do the same motion over and over again it becomes a muscle memory. I do flat and S grinding always from the right side of the belt, which people find totally weird. It feels perfectly natural after a while.
     

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