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120v Single Phase Vfd

Discussion in 'Grinders' started by Shadnuke, Feb 3, 2020.

  1. Shadnuke

    Shadnuke Disabled dreamer...

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    I've been taking to some folks, and it looks like I've found an inexpensive way to run a VFD on a single phase 120v setup. I'm running a 1hp 120v single phase setup on my grinder, and I was doing some reading, and this little device came to my attention. An inverter frequency converter. You can run 120v single phase input, and it will give you 240v 3 phase output! Found a few different options in my searches, and they run from about $60 bucks for a Chinese brand on eBay, to a few hundred bucks for name brand controllers. I've read in some other forum posts that there are guys running both the Chinese brand and the name brands and I haven't seen any posts about any of them having issues with either of the cheaper models or the more expensive models. I will have to check my motor, to see if it has the ability to run 3 phase 240v, because I may be able to run power out to the shed. If I can switch, I will just go that route, but if I can't, I will pick up a cheap inverter frequency converter, and see how it works!
     
  2. dancom

    dancom Dust Maker Best Shop Tool

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    Hi Kevin,

    Lots of moving parts here.

    Yes, there are single phase to three phase VFDs and many are inexpensive. I have two of them in my shop running grinders. (Will post some pics below.) One of the reasons they are inexpensive is that they are open chassis which means you really should protect them from the environment. In other words, put them into an enclosure of some sort to keep the dust away from the electronics.

    Another factor is that, as you mentioned, these VFDs drive three phase motors. Three phase motors are super reliable and generally the lowest cost motor per kW compared to single phase motors since they have no capacitors or centrifugal switches like single phase motors. If you have a three phase motor, then it makes sense to get a VFD.

    Be sure to look for a VFD that can operate with 115V in and output 230V. Not all have this voltage doubling ability. The majority of VFDs are outputting the same voltage as they are getting in, so 115V in gives you 115V out. Or 230 V in gives you 230 V out. Both of mine are 230V in and 230 V out.

    These drives can be a bit finniky to setup, often coming from factory with the weirdest settings loaded. So be prepared to read the broken English manual, reset to factory defaults and start fresh changing some setpoints through the keypad. Not the end of the world.

    Here are some pics of my 2 hp Lapond (Cheap-o VFD) as I put it together and made the remote for it. It's package in a fibreglass enclosure which saved me some moola. I bought the remote keypad/display with this one so I could make the remote more useful.

    [​IMG]


    [​IMG]

    [​IMG]

    This is my HuanYang VFD (2 hp) that I put into a steel enclosure. I got lucky and found the enclosure on Kijiji for $60.
    [​IMG]

    Calculations that I made when packaging my two open chassis VFDs would suggest that with the enclosure, fuses, switches and so on, makes the cost for the inexpensive VFD after packing only slightly less than a completely sealed KB Electronics VFD of the same power rating. In saying that, there may be some cost savings you can apply given your surplus and circumstances. Maybe you have an enclosure already, or have some fuses or terminal blocks already. That's great.

    If you have a VFD in mind to go with a three phase motor let me know, I can look up the specs and tell you if it's going to work for you.


    Dan
     
  3. Shadnuke

    Shadnuke Disabled dreamer...

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    Thanks for the info! I will try to make it out to the shed tomorrow, and take a look. I believe the motor can be wired 3ph but I can't remember. I remember seeing something, but off the top of my head, I'm not sure, and might just be a 1ph.
     
  4. Shadnuke

    Shadnuke Disabled dreamer...

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    Just thought to check my order history for the motor. This is what I'm running...

    IronHorse standard performance AC induction motor, general purpose, 1hp, 1-phase, 115/230 VAC, 3600rpm, TEFC, 56C frame, rolled steel, rigid base/C-face mount.
     
  5. dancom

    dancom Dust Maker Best Shop Tool

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    Hi Kevin,

    I have a very similar motor on my horizontal belt grinder. A single phase motor is constructed in a different way (# of windings, pole spacing, capacitors etc.) than three phase motors. Unfortunately, to go with a VFD you'd be looking at replacing your motor with a three phase motor.

    In all fairness, I have heard cases where people re-wiring a single phase motor into a pseudo three phase motor e.g. use the start winding as a phase winding, but this isn't a recommended practice and derates the motor power substantially.
     
  6. Shadnuke

    Shadnuke Disabled dreamer...

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  7. ccady

    ccady New Member

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    It's really not worth the hassle of rewiring a single phase motor into a three phase. I've purchased 3HP 3ph motor second hand new for $100 + tax before. Plenty of deals if you shop around. At worst, it's a $100 mistake. I wouldn't exactly say screwed.

    I purchased a VFD, drive wheel, AND motor and then decided to go with something else.....in the grand scheme of things, not the end of the world.
     
  8. dancom

    dancom Dust Maker Best Shop Tool

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    If you are like me there's always a project lurking in the back of the mind that can use a motor...or two.
     
  9. ccady

    ccady New Member

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    or 4 or 5........in general, it's a good practice to buy when it's cheap. However, I tend to overbuy.

    As you stated in your guides, you picked up a $35 2HP WEG motor for $35. At that price, why would you even consider modding a motor?
     

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