Can I handle a 3 phase machine?

silverforgestudio

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OK so I am in a position to get a 3ph mill with 3hp motor... but I have residential wiring (max 220v single ph 20 amp circuit)...

Mill is good price, low mileage (only driven to church on Sundays- or was that sunny days? HA!) and in decent condition...

So my questions are:

1- Do I invest in the rotary phase converter (And how loud are they)
2- What are the pros/cons of the 3ph starters that convert after starting to single phase?

I will be doing aluminum and stainless with brass/bronze mixed in- Im a hobby jobber for now so nothing ultra industrial is needed.

Gotta convince myself I can DO this before I toss the $$$ and drag home a beautiful piece of machinery that is- well, a doorstop. (And along the way- my wife is all for it if the price is right for the solution as well so SWMBO is on-board!)

Thanks in advance and I hope everyone had a great and jolly Fourth! For all who have served to protect my rights- I SALUTE YOU!

Kerri
 
I have two American Rotary phase converters. They are very quiet and made here in America with awesome support.
 
Quite a lot of 3 HP three phase machines are operated in residential spaces. They can be made to work using either a VFD or a rotary (or static) phase converter.

Edit: Full load current at 220v for a 3 HP, 3 phase induction motor is around 10 amps.
 
I have a RPC, but the wife wouldn't let me run it at night due to keeping the neighborhood school kids awake. I have the parts to rebuild it and hopefully quiet it down some, but it's now low priority. All of my equipment is now on VFDs. The RPC will be sold off whenever I get it rebuilt. For a single machine, I would go VFD before RPC, and would never consider a static starter.

Would this be that round ram BP that's been on Craigslist?
 
Another vote for a VFD, buy the mill if it is in good condition and what you want. Static converter essentially derate the motor by 50% and they can overheat the motor, I would not go that that route. I have heard very quite RPCs if done correctly, but I think it is easier and more cost effective to go the VFD route for a 3Hp setup. I would not worry about 3 phase, overall it will operate much nicer than a single phase machine.

If using a vari-speed head, you may want to have the VFD set at a fixed frequency and use the mechanical speed control, if a pulley setup, then definitely the VFD route adds a lot of flexibility to the machine speed.
 
Another vote for a VFD. I have a Phase Perfect solid state converter, basically a VFD with out the variable frequency but it will handle switching loads and 10 hp. I recently bought a 3 phase radial arm drill press. It sits on the opposite side of the shop from the rest of the equipment. Rather than run 3 phase wire to it I bought a VFD to feed it from 220 v single phase which was close. The solid state supplies use virtual no power in standby and the Phase perfect is 95% efficient at full load so big power bill savings. Both are visually silent too.

Greg
 
3 hp is 750 watts X 3 which is about 2250 watts or just shy of 10 amps as mentioned above but starting current a bit more.

Do go with a vfd but it will need derating at single phase input and different models are different so after you select the model type of unit then download the manual and verify exactly which one you need for your mill.

The vfd can cheat a bit in that it converts ac to dc and uses filter caps to make better dc before making the 3 phase output and these caps help out with short periods of higher current.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
I have a RPC, but the wife wouldn't let me run it at night due to keeping the neighborhood school kids awake. I have the parts to rebuild it and hopefully quiet it down some, but it's now low priority. All of my equipment is now on VFDs. The RPC will be sold off whenever I get it rebuilt. For a single machine, I would go VFD before RPC, and would never consider a static starter.

Would this be that round ram BP that's been on Craigslist?

Not the one on Craigslist in hampton roads Randy- its actually near Richmond. Cool to see another HR fellow around here- Deep creek or Great Bridge area?


I would be more concerned with the mill itself and how worn it is rather than how to power it
Mark S.

THAT is true Mark- it is an as-is sale. I will be getting my hands on it for a bit of a tester look-see (its not under power) Tuesday- Ill know a LOT more about it then!


3 hp is 750 watts X 3 which is about 2250 watts or just shy of 10 amps as mentioned above but starting current a bit more.
Do go with a vfd but it will need derating at single phase input and different models are different so after you select the model type of unit then download the manual and verify exactly which one you need for your mill.
The vfd can cheat a bit in that it converts ac to dc and uses filter caps to make better dc before making the 3 phase output and these caps help out with short periods of higher current.

THANK you for the tidbits on the VFD functionality- If you havent guessed Im a home shop guy still learning all the stuff... this is cool info!

Thank you guys to every one who replied! Ill post more on Tues when I get to put my voltage tester to the motor and a few switches... I know its missing the XY table feed handle- so no telling what ELSE was scrapped/swiped/pulled off it.

The NEXT adventure is getting the thing home... lift gate rentals here I come! HA!
 
Lift gates suck for lifting milling machines. They are slippery, often not level, and there is nothing to keep the mill from sliding off onto the ground. You can also get badly hurt. I recommend a low trailer, preferably a drop deck (drop bed) trailer. All you need beyond the trailer and something to tow it with is a come along, some 3/4"pipe sections for rollers, a few short 2x4's and 4x4's, a pry bar, and some good ratchet tie down straps for securing the mill for the road.
 
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