I know this is off topic. I tried to get my question answered elsewhere...but I need some HAMB type help, you know, do-it-yourself, with what ya got. My old 16" Monarch lathe has a Toshiba 3 phase 2HP Induction Motor. I have a 220 single phase circuit run to a diconnect then to a static phase converter. The lathe has a Fwd/Off/Reverse drum switch on it. My question... Do I need anything else? Can I just run the 3 legs from the phase converter to the drum switch and then from there to the motor? I asked elsewhere and was told I needed relays and thermal/overload protectors and alot of other $$$$tuff. I have never messed with any 3 phase, but my brother's old Lodge and Shipley lathe is hooked up like I propose to do and it is still running, but I don't know what kind of motor his has (besides 3 phase). So, can I just hook up what I have and make Hot Rod parts? That's what its all about anyway... Thanks, Neal
My Monarch had a 3 phase also. I talked to a friend who owns a motor repair service. He said it aint worth it, get another motor. I went to other forums wondering about phase converters and it really aint worth it. You lose a lot of horsepower running a 3 phase on 220v
Looking at a Surplus Center catalog, they say for their phase converters, a 3 hp. motor will produce 2/3 of its rated hp. Unless you were really makeing some super heavy cuts, I don't think you'd miss the 33% loss. Might want to watch for R.P.M. loss though.
Yea, but I already have the phase converter and a nearly new 3 phase motor that is already on the lathe...and reversable single phase motors are kinda hard to come by. If I can wire this up with what I have, I would just like to do that. If I have to buy a motor starter or some other $pendy parts, I may consider a new single phase motor. Neal
I heard this-am I wrong, or is it possible to run a 220 -3 phase motor on 220 single phase current after it gets up to operating speed?using a single phase motor to act as a "starter"?
The correct why is to use a motorstarter because of the overload protection for the motor, the fused disconect only protects the wire,the motor will smoke before the fuses trip and overloads are resetable.But will work the way you want to wire just harder on the disconect and less motor protection.You can look in yellow pages for a electrial junk(used parts)yard that should save sum $$$$ PATINA
After hooking up the lathe to the 3 phase power an electrician would want you to have some sort of amperage protection. I would find out the FLA (full load amps) of the motor and install a fused disconnect to protect your motor. Cheap insurance for your equipment. While looking for the FLA of the motor you might find out that the motor itself is thermally protected on its own. There are a majority of electric motors that have there own thermal protection. If it is, then it should be fine to hook up the lathe to the phase converter. The only other thing you may need is a motor starter, but the lathe might have one on it already. Geno
If'n anyone sees it that cares you will want to put some kind of a disconnect at the machine. A plug and socket would do, or a relay-many different ways to do it. They (the electric cops just don't like to see it hard wired without a disconnect) Don't ask me how I know. If you want to get full power, it's easy. Send me an email and I'll send you the whole scoop.
Reversable single phase motors are not that hard to find.Many single phase motors can have the rotation reversed by switching a couple wires inside the motor. Get one of these, and wire a DPDT switch of the correct amperage into this circuit so you can switch it either way. You then need two switches, one for off/on, and the other sets motor rotation. I did this on my Bridgeport, using a universal end mount motor from W W Grainger. I made an adapter out of a one ton Chevy truck wheel to mount the motor on the original bracket. FWIW, Northern tool lists a 5 hp compressor motor for under $200 that would run a lathe just fine.
Neal, Switching phases on a 3 phase motor changes the rotation. If you have the phase converter wired to produce the third phase, you should be able to switch legs through the fw/rev switch. If you can email me a drawing of how you are wiring this I can try to help you set it up. I need the wiring from the switch and phase converter. Using a Magnetic starter with overload heaters will protect the motor but may not be necessary. If the fw/rev switch is rated for your motor switching, which it should, you should be ok. Since it will only be running when you are operating the lathe, you will hear it if it starts to "single phase". email me gordonb@broadcom.com
Neil-I worked a electrical supply house--email Chris.Nichols@gbe.com or call me 800-326-3463 and I'll hook you up(no pun intended)
Neal,have you been to www.practicalmachinist.com ? they have forums for 3 phase/VFD and a Monarch forum too-george
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