Bought 3/4hp 3phase motor by mistake, what to do with it

[dvo]

Other than a door stop what can I use this thing for? rotary phase converter?(I know nothing about the subject matter)

[Hal]

Buy a VFD and you have great motor for most anything.

Hal

[Duffy]

Buy a phase convertor to go with it and carry on. A teco convertor will cost about $120.00, and you will NOT be sorry.

[Forrest Addy]

I vote for the VFD (it will cost you about $100). Put the motor on your drill press and you can plug the VFD into a 115V wall outlet. Here's a link:

http://dealerselectric.com/item.asp?cID=28&PID=1104

You will kiss the ground I walk on for making this suggestion.

[danlb]

Would it be worthwhile to put one of these on a 9x20 lathe, to replace the 3/4 horse that is on there now?

Dan

[Forrest Addy]

Would it be worthwhile to put one of these on a 9x20 lathe, to replace the 3/4 horse that is on there now?

Dan

Hell yes, but you might be happier with a little more HP.

[rws]

You just can't beat a VFD on a lathe.....

[Deus Machina]

I vote for the VFD (it will cost you about $100). Put the motor on your drill press and you can plug the VFD into a 115V wall outlet. Here's a link:

http://dealerselectric.com/item.asp?cID=28&PID=1104

You will kiss the ground I walk on for making this suggestion.

Well, hello...

Do those work alright on 110, 15-amp circuits? And do they have a 115 -> 220 single-phase?

[BigBoy1]

Make your own rotary phase converter

I used a small 3-phase motor to build my own rotary phase converter so I can run a larger HP 3-phase motor on my lathe. Your 3/4 HP just might be just the ticket to do something like that.

[J Tiers]

use more than 3/4 HP on a 9 x 20?

OOOOOOKAAAAAYYYYY

Seems like that is enough to take two turns and a half hitch on the bed of a 9 x 20.

I have a 1/3 HP on a 10" Logan , and have NEVER had any limitation from the motor whatsoever. And I KNOW that machine can stand a larger motor just fine.

JT

I used a small 3-phase motor to build my own rotary phase converter so I can run a larger HP 3-phase motor on my lathe. Your 3/4 HP just might be just the ticket to do something like that.

The usual rule is the reverse..... A 1 HP RPC for a half horse load, 2HP for 1 HP load, etc.

I am not sure how you have the "small" RPC set up to start the "larger" motor on the lathe. if it works, I guess it works, but...

[jep24601]

My 13" swing LeBlond came with a 3/4 HP motor.
(Though maybe that was to limit damage as it was originally supplied to a high school)

[lakeside53]

3/4 hp on a vfd will only give 3/4 hp around it's nominal frequency of 60hz. At say 30hz, you'll get about 3/8 hp..

If it worries you (shouldn't) then just set the VFD motor current so that it can only get 1/2 hp out.


Yes, you can buy a VFD that runs from 120v, BUT... it won't run on a typicial GFCI (if that bothers you). There is no "fault" - just the vfd noise currents being filtered to ground inside the vfd.

[dvo]

I used a small 3-phase motor to build my own rotary phase converter so I can run a larger HP 3-phase motor on my lathe. Your 3/4 HP just might be just the ticket to do something like that.

This sounds like a better use for my little motor. Please elaborate? What was the hp of your rpc and hp of the lathe motor? and what the max hp the rpc can drive?

[Forrest Addy]

dvo. I don't think I'm overselling when I suggest you research the VFD ad get some referrals. You havve a several speeds on a lathe, mill, drill whatever. The variable speed feature of the VFD fills in between - an important thing when you need lower speeds than you can gear for.

You may wish to avoid what seems like complication but installing a VFD is no more complex than building a phase converter.

I'm sure a few will chime in with VFD testimonials. I have four on my machine tools.

[ironnut]

Send it to me

Actually Forrest's suggestion is an excellent one. I replaced the 1 hp Taiwanese motor on my 30 year old Grizzly mill with a 3/4 hp 3 phase 1725 rpm motor. It is so sweet. The VFD was just over $100. It will drive a 1 hp 3 phase 220 volt motor while being fed by 120 volt single phase power. It has a surprising amount of torque at low speeds as the VFD can push more current to the motor in an attempt to maintain the speed setting. Reversing is very easy. I love not having to change belt positions to get correct speeds. I can run 3/16" to 1/2" drills with good results, even larger if I take it easy. I would never go back to the single phase motor.

I don't believe a rotary phase converter based on a 3/4 motor can safely run a 3 phase motor larger than itself. I thought that typically if you wanted to run a 3 hp 3 phase motor, that you needed a rotary converter based on a 5 hp motor.

gordon