VFD and motor selection

[wildcat]

I found the following motor (on Amazon of all places)

http://www.amazon.com/exec/obidos/AS...6-20/ref=nosim

which seems to be the same one that Aaron suggests using:

http://www.industrialhobbies.com/how...or_and_vfd.htm

I also found the following VFDs that seem to be suitable

http://www.automation4less.com/store...=L200%2D015NFU
http://www.automation4less.com/store...SJ200%2D015NFU

The rep from Automation4Less told me that a 2HP VFD will be just fine on a 2HP motor. He said that Hitachi says the derating for single phase use is no longer necessary. He also said that the L200 will be just fine and there is no need to get the SJ200 unless higher starting torque is needed.

Many here have experience with 3 PH motors and VFDs and I would value your opinion on installing a motor like this and similar VFDs. Will a 2HP VFD be fine or should a 3HP VFD be puchased? Anyone have any knowledge of why the SJ200 should be chosen over the L200? Is the maching that is necessary (D90 to D80) something that can reasonably be done in a home shop? Does it strictly involve cutting the length of the shaft, turning the shaft, and cutting the keyway deeper again? Or is there something else to the operation making it best to go to the pros?

[DiscretePID]

I have a Lathemaster ZAY7045FG (very similar machine) and I just bought that exact same Leeson 2hp motor from http://www.electricmotorwarehouse.com which is the same seller in your Amazon link. I also bought a 3hp SJ200 from http://www.driveswarehouse.com Yes it is overkill for this application, both in terms of HP rating and being a sensorless vector VFD. A 2HP V/F would probably work just fine, but the difference in price is not all that much. I would rather buy a bigger and better drive in case I may want to use it for something else later.

I also find the SJ200's detachable control panel a must have. It makes mounting the drive much more flexible. A few other VFDs that have this feature too. I don't believe the L200 does.

Here's what you need to do to convert a D90 motor to fit:

1. Turn output shaft diameter down to 19mm
2. Cut new 6mm keyway (on opposite end of what's left of the old keyway)
3. Shorten the shaft length by 3mm

Shortening the shaft length is not all that critical. Based on my preliminary measurements, I told the machine shop not to shorten it at first. After I got the motor and trial fitted onto the mill, I found the mill has a dish shape at the bottom of the shaft "well", which kept the tip of the new motor shaft from going into completely. It was only about 1~2mm off. I just grinded a little bit off the shaft tip with an air cutoff wheel, and it fitted just fine.

Turning the shaft down to 19mm is no big deal if you have a good size lathe. Cutting the new keyway is also easy if you have a working mill and the right tool. Well, I have a brand new ZAY7045 mill and a brand new 8x14 lathe, but neither has been set up properly yet and both are taken apart for VFD retrofit. So it's the chicken or the egg thing... I suppose I could set them up first to machine the shaft, but the amount of work is just not worth it.

Anyhow, I had the same folks at electricmotorwarehouse.com do the machining - $100 per motor. It isn't cheap, but I get the motor and mod done all in one order, shipped to my door ready to install. I can get it done cheaper (maybe $40~50) at a local motor shop, I'm sure, but that will involve at least two trip to the shop. I'd like to think my time is worth at least $50. Not to mention the warranty issue for work done by 3rd party.

Here is the contact at electricmotorwarehouse, in case you choose to do the same as I did:

Barry Catrell
Winans Electric Motor Repair Inc.
info@electricmotorwarehouse.com
http://www.electricmotorwarehouse.com/
Toll Free 1-877-986-6867
1-810-744-1240
Fax 1-810-744-1424
Monday thru Friday 7am to 4:30pm EST

Barry is very nice to work with and responds quickly to my emails. Tell him the guy in TX that just had two motors done sent ya.

[Randall]

when I was going thru this same choices I was told that a 3hp would be a better choice. the increase of speed will need some of that HP due to the gearhead. I never tried the 2 hp motor so no comparison to go by. I am happy I went with 3 phase and I went with a 3hp vfd and never had a problem with overloading it.
Randy

[wildcat]

DiscretePID - Your configuration sounds identical to mine. I just placed the order for the motor and VFD. I am curious, what service (breaker size + wire size) do you have in place for the VFD? The documentation says it draws 24A?!? I am hoping that is at full 3HP load and that I can continue to use 12 awg wire with a 20A breaker.

[DiscretePID]

The VFD will only draw what it needs to drive the motor. The Leeson 192070 2HP D90 is rated at (220V 3ph) 6.0A full load and 6.8A Service Factor. Even if you double that to 12.0A to account for the 1ph conversion + inefficiencies, you will still be at the safe limit for continuous current draw of 20A breaker + 12AWG. I thought about this when I decided on the 3HP VFD + 2HP motor. It was very tempting to go 5HP VFD + 3HP motor, but I just had to realistic about my cutting rate requirements.

I haven't set up my ZAY7045 yet. I did briefly hook up the VFD and motor soon after I received them to test for DOA. I did this off of my garage's 20A 220V circuit for the air compressor with no problem. At next to no load, of course. Because I have a Sieg X3 ready to use, I will take my time to set up the 45. Buidling the shop will come first. The GE Workshop load center I bought for it has 12 positions and can easily handle 3 (or more) 2-pole 220V breakers, so I can always plan ahead for upgrades.