Running on a rotary phase converter

Thanks for all your responses. Now I just need to get the nerve to hit the "complete checkout" button on the lathe.
 
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I have an American Rotary AMP-10 for my 3 phase, 220V, 5 HP PM-1660TL. It is perfect. I will not switch to a VFD.

Make sure you get a big enough circuit breaker on your new RPC. I needed 30A for the machine above. The highest speed (1800 RPM) would trip a 20A circuit breaker. I put in a 30A (easy job AND American Rotary was very helpful with this task) and that was fine.

American Rotary has good customer service.
 
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tjb said:
While we're on the subject of RPC's, I have a question for some of our seasoned veterans. Can more than one piece of equipment run on a single RPC at the same time? For example, if I have a 3hp mill and a 2hp 6" sander could both be run simultaneously by different operators on the same 10hp RPC? Just wondering.

Regards,
Terry
Click to expand...

I wonder if this could trip a circuit breaker, either on the RPC or on the main breaker panel (on the side of the house).
 
I have a 10hp American Rotary. My lathe is 7.5hp. The mill is 3hp.
I never run more than one machine at a time.
American Rotary suggested a 15hp RPC.
My lathe motor is running before I engage the clutch.
Ulma Doc and others said I would be fine with a 10hp RPC.
I saved over $600 and the 10hp is flawless after 2 years. It runs several hours a week.
 
I found these notes on my phone for how I wired up my 30A plug and receptacle.

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American Rotary sold me 5-6’ of an SO cable, and at another point I bought the same from Home Depot. Each wire was 8-10 AWG (I don’t remember).

In both SO cables, the wires were green, black, red and blue. Of course, you’re going to use green for ground. It also makes sense to use red and black for the T1 (X) and T2 (Y).

If you get the X and Y wrong, the motor will run backwards. I don’t know what that would mean for your bandsaw, but it doesn’t cause any problems with a lathe. I did it wrong the first time, and after I saw the result I just switched the two and now everything is the way I want it to be.
 
I had a surprise wiring up mine. I didn't think the generic schematic in the manual was useful, since I have the heavy version of my mill and the manual covered the range. There are a lot of electrics in my mill's panel enclosure, but no elec-tron-ics at all. I just traced out the wires to ensure I wasn't hooking up the wild leg to the 110v accessories, not that it should matter for a lamp, fluid pump, or power feed. Anyway, I knew I'd be 50/50 on getting the rotation right. I fired it up, and it turned the right way. Then I tested my drill press, which ran in reverse. Well, it was easier to swap the wires in my RPC panel, so I did, and the drill ran correctly... and so did the mill. Apparently the forward/reverse start circuit is indifferent to leg phasing. I did not expect that!
 
Janderso said:
I have a 10hp American Rotary. My lathe is 7.5hp. The mill is 3hp.
I never run more than one machine at a time.
American Rotary suggested a 15hp RPC.
My lathe motor is running before I engage the clutch.
Ulma Doc and others said I would be fine with a 10hp RPC.
I saved over $600 and the 10hp is flawless after 2 years. It runs several hours a week.
Click to expand...
The big limiting factor seems to be either 'peak torque' and 'startup torque'. Something like a lathe with a clutch is going to have very little start-up-torque, and you'll likely have a hard time using 7.5 hp worth of power in a lathe.

My 10 hp motor on my shaper however runs a hydraulic pump. My 20 HP RPC will sometimes 'stall out' and not be able to start the shaper if the hydraulic pressure in the system is too high. It is close enough that on a 'cold start' if I try to run my power-feed (a 1/2hp motor) while starting it up, that it stalls pretty reliably.
 
ErichKeane said:
The big limiting factor seems to be either 'peak torque' and 'startup torque'. Something like a lathe with a clutch is going to have very little start-up-torque, and you'll likely have a hard time using 7.5 hp worth of power in a lathe.

My 10 hp motor on my shaper however runs a hydraulic pump. My 20 HP RPC will sometimes 'stall out' and not be able to start the shaper if the hydraulic pressure in the system is too high. It is close enough that on a 'cold start' if I try to run my power-feed (a 1/2hp motor) while starting it up, that it stalls pretty reliably.
Click to expand...

I had the same issue with running my 3hp horizontal mill on a 5hp RPC... The motor on the mill drives a hydraulic pump. On startup, it would really pull the RPC idler down for a few seconds. After the mill reached its running speed, the RPC powered it fine. I upgraded to a 7.5hp RPC... it doesn't have any problems starting the mill.

-Bear
 
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