Rotary Phase Converters - revisited

[newbury]

Best/most recent thread I found was Phase Converters

For those that may remember I've a shop with about 5 pieces of 3 (edit) phase equipment bought from an auction of the closing of a high school wood shop. Planer, bandsaw, tablesaw, radial arm saw, scroll saw. Had plans to build an RPC based on my son saying he would help. Bought a used but functioning 10 h.p. motor. And there was a guy on e-bay selling "kits" for a reasonable (~$150) price.
Then my son backed out. Then COVID came along. The ebay "kits" disappeared. So as life interfered everything just got stored.
So now it is all like a "barn find" and I'm wanting to start again.
I realize a lot of people will recommend "VFD's". But I'm also looking at getting other 3 phase equipment, recently got 2 more 7.5 hp 3 phase motors ($25@), and it seems there are now a lot of "Rotary Phase Converter Quick Build Kits" on the market for what seems to be reasonable prices.
So I'm looking again for any advice on recommended RPC kits.

 

[LouNY]

Here is a you tube video on making one, just be sure to watch the second part also as he makes an error in the initial build and corrects it in the second video.

 

[DarkBlack]

Best/most recent thread I found was Phase Converters

For those that may remember I've a shop with about 5 pieces of 2 phase equipment

I’m assuming that’s a typo, and you meant 3-phase.
VFD’s are the most versatile solution for just a few pieces of equipment, and the prices are reasonable.
When you start to get into a sizable shop with lots of 3-phase equipment, it’s time to contact your utility company, and get pricing on a feed.

 

[LouNY]

Not in my rural area, if it isn't going right by you it is exorbitant to get 3 phase run in. I seen several shops with a few 3 phase motors that actually run a 3 phase generator to make power when the equipment is needed.

 

[DarkBlack]

I’d only go the generator route over VFD’s if I didn’t have any electricity, like at a sawmill.

 

[caver]

plus you waste more energy with a rotary phase

 

[newbury]

I’m assuming that’s a typo, and you meant 3-phase.
VFD’s are the most versatile solution for just a few pieces of equipment, and the prices are reasonable.
When you start to get into a sizable shop with lots of 3-phase equipment, it’s time to contact your utility company, and get pricing on a feed.

yup typo

And I had contacted my utility company. Back then (10? years ago) it was going to be about $100K, about 1/2 mile or so of run.

Looking at prices for VFD's just one for my larger motors will cost as much as a RPC kit which will run all of my equipment.

I had also looked into running multiple pieces of equipment off one VFD but everything I read pointed to that would require reconfiguring the VFD for each piece of equipment.

So I'm looking again for any advice on recommended RPC kits.

 

[CliffordK]

If you're running small equipment, say mills, lathes, etc with 1 or 2 HP motors, then the VFDs work very well, with the benefit of easy speed adjustment.

Something like a welder that sucks down a lot of power and doesn't need the variable frequency, the rotary phase converter might work.

 

[5030]

Myself, I run a commercial Gerhardt-Werner converter but only for starting up one machine because once it's started, it will provide adequate enough 3rd leg to run the other machines, so it gets shut off.

 

[etpm]

The least expensive way is the RPC. For machines more than 3 hp most VFDs require 3 phase input, so you would need an RPC anyway. Also, if you don't need variable speed or soft start, a VFD is an unnecessary complication. Furthermore, each machine would need its own VFD.
Eric