??Phase Converter for South Bend & Supermax Mill??

Hi all,
I have a SB 13" and a Supermax 1 1/2 VA mill. Both have a 3 phase motor and each pushes 2hp. I have 120/240 coming out of the house ""single phase"" I'm assuming. I'm thinking a Rotary Phase Converter would be the best set up for me. Type of work i'm looking at doing is strictly gunsmithing. I'd like something reliable that wont give me a headache later.

Any recommendations would be greatly appreciated.

Thanks fellas.

I just set up a Rotary Phase converter to run my SB lathe and a Drill Press/ tapping machine. Easy to wire and I found the price to be fair. If you want more info or a pic let me know.

Gary,
Definitely interested in the pic and info. Any details will help. What made you decide on this set up?

I wanted to run two machines from one supply. I bought a 5hp unit from American Rotary. They have a good price and customer service---- 2 biggies for me. I will get you a pic later today.

Here's the pic-----

This forum contains schematics for most of the wiring configurations for rotary converters. All you need is a 5 HP, three-phase motor, two suitable relays, a few start (plastic) and run (metal) capacitors, plus some form of frame or box to hold it all. It is not complicated to build, and you can get plenty of assistance over on that forum. I built mine, and I am not an electrician. Warning: Most licensed electricians have little or no experience with converters. My electrician did not believe that it would work until he saw it and put his voltmeter on it. Regards, Clark

I use the same rotary changer to run my lathe & briggeport, verry good company to work with,

Sealark37,
Do you have a link or title for that specific forum or thread?
I also looked at American Rotary's converters and they look nice and professional.
Since I'm a huge DYI kind of guy and not in a big hurry, I'd like to take a crack at possibly doing it myself.

Gary,
If I decide to go this route, thats the same American Rotary converter I was looking at. I see them on ebay for a reasonable price. Did you wire it up to your house?
Thanks again for the pic!

My shop has it's own meter and fuse box. I did run a seperate 20 amp breaker to power the box. The biggie for me was how darn easy and fast this was.

Converter

I have 2 converters, use them every day, but will not go that way again.

You can purchase a VFD for less and not have to worry about chewing up power / listening to it run when a tool isn't actually spinning.

Suggest you look that direction before you make up your mind that rotary converter is the way to go.

Under "Forums", scroll down past "Antique Machinery" and "Gunsmithing"to "Transformers, Phase Converters, and VFD". The first item on this forum is the Phase Converter Plans ans schematics.

the way we set upmy shop with a rotory converter was to run from the converter to a 3ph. breaker box. that way it is easy to add machines. also if i ever get 3 ph. run into my shop everything already set up for it.

Rotary or VFD?

Now I'm thinking the VFD may be the way to go?

I appreciate the knowledge base here. Very helpful.

Since I'll probably only run one machine at a time and dont plan on opening a shop, strictly home garage work, what are your thoughts on the VFD over the rotary phase converter?

I like Golts Machinists recommendation on cheaper, quieter, and doesnt chew up a lot of power.

Sealar37, I'll do my research in that converter plans forum. Thank you!

I recently rebuilt, and sold a 3ph Induma mill. During the build process, in order to check the functions/condition of the Induma, I ran a 'drop' off my SB's Hitachi VFD. Kept it hooked up some 3-4 wks, eventually using it to demonstrate the Induma to the buyer.

This was a temporary set-up, but I could easily see that a switch to change between the 2 could be rigged to go between the 2, and made permanent. The SB is 2hp and the Induma was 1 1/2hp, and the Hitachi is rated at 2hp, and in my home shop the need to run both machines wouldnt be an issue. I think it would be a good set-up - allowing all those wonderful features of a VFD on 2 machines

Gary Max said:

I wanted to run two machines from one supply. I bought a 5hp unit from American Rotary. They have a good price and customer service---- 2 biggies for me. I will get you a pic later today.

Here's the pic-----

Click to expand...

I'm looking to do the same. What is the amp rating for the 5 hp model you have?

Edit: Found it

Bill Pace said:

I recently rebuilt, and sold a 3ph Induma mill. During the build process, in order to check the functions/condition of the Induma, I ran a 'drop' off my SB's Hitachi VFD. Kept it hooked up some 3-4 wks, eventually using it to demonstrate the Induma to the buyer.

This was a temporary set-up, but I could easily see that a switch to change between the 2 could be rigged to go between the 2, and made permanent. The SB is 2hp and the Induma was 1 1/2hp, and the Hitachi is rated at 2hp, and in my home shop the need to run both machines wouldnt be an issue. I think it would be a good set-up - allowing all those wonderful features of a VFD on 2 machines

Click to expand...

Since both machines are the same power so would run OK from the same VFD a permanent fix like Bill mentioned is possible.

For my setup (1 HP SB 13" and 1 HP pillar drill) I took note of the fact that the VFD should not be run without a load attached, and considered the dangers of one machine being able to start the other by mistake (switches set wrong) or both machines being powered up together.

My solution was to use 2 switch disconnectors to isolate each machine from the VFD, with 2 auxiliary changeover switches piggybacked to each disconnector and a rats nest of LV wires between the machine switches and the VFD 12v inputs via the changeovers to form an interlock such that with one disconnector on and the other off, only the switch on the machine with power would start the VFD, and with neither or both disconnectors on, none of the machine switches can start anything.

The first setup only had the interlock wiring on the +ve side of the control system, but I noticed the switch on one machine could start the other so ended up adding the second aux contacts to both and interlocking the common line too. Even though I am the only one using my machines and I can't use both at the same time, I feel this is the minimum amount of idiot-proof I need to build into the wiring.

Don't ask what I did with speed pots and emergency stops - the latter are easy, the former I can't even remember if I sorted it, I don't vary the speed on the drill very often (apart from changing the belts)

Decisions decisions

Holy Smokes Jimwallis! Where did you learn how to do that? Keep in mind I'm a beginner here. However, I'm not in a hurry and dont mind picking up a book or run a search on the net in order to figure out how to wire up a few things.

Bob308, I like the 3ph breaker box idea.

Although the rotary phase converter sounds a lot easier to handle, I wouldnt mind the power savings and quietness of a VFD.

How much power does one save on a VFD compared to a RPC? What about longevity and the abuse it might take during the on/off switch operation? A rotary phase converter sounds to me like it may be more robust and meant to last a long time. VFD sounds a little more complicated, but I'm sure if its rigged up right it should do the job for a long time, especially for a garage gunsmith.

CIENTIROS said:

Holy Smokes Jimwallis! Where did you learn how to do that?

Click to expand...

I have to come clean, I have a friend who makes switchgear panels for a living, he did a preliminary sketch for a circuit diagram and told me what the bits are called, and I found the bits and modified the sketch as necessary to suit my control system (I'm an engineer, well naval architect, so given a little info I am usually able to work out the rest ).

The tricky question is do I still have my sketches - I have a feeling I left them in the shed near the VFD, I also have a feeling they are the bits of paper I found on the floor the other day in a puddle and unreadable

It's probably not a beginners project to be honest, and if you are likely to use more than 2 machines or use more than 1 at a time, it won't be a suitable, but a rotary converter will be.

Oh yes, the other thing to come clean about - by the time I had bought all the switchgear etc to do this, I probably wasn't far short of being able to afford a second VFD.... but thats for 1hp not 2hp.