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What do I need

What do I need

What do I need

(OP)
Any help or advise would be greatly appreciated.
 
 I seen a small businessman who had his entire rural business running on a creative power supply, he had a single phase 230 VAC service supplying a 230 VAC 60 HP 3phase motor, he would simply turn on the single phase 230 power on to the motor and then pull a rope to start the motor turning in the correct direction and the motor would create the third leg of the 3 phase, then he could start various other milling machines, lathes and saws all of smaller (1-2-5 hp) as required. His operation has run like this for over 20 years with no problems.
 
I have a project which requires 3 phase power but only single phase is available. The customer already has three machines each of which are running on it's own roto-phase adder. We had added the equipment over several years and managed to find a rotor-phase adder for each piece of equipment. I installed these units several years ago and they work great.  The phase adders are of various types (one is home-made), one even has a nameplate which only says "Start 2 HP run 7 HP".
 
The customer purchased another machine of which he plans to run only sometimes, and we had planned to use one of his existing rotor adders to supply power for the equipment, but they were to small. (The customer had purchased the machine from another person who ran it on a home made roto-phase-adder for years and all of the wiring was 10AWG)
 
It turned out that the roto phase adder we had was two small to start the machine. And I would like to know how to calculate what is needed to build a roto-phase adder. I made a drawing of a homemade unit that I had seen and it seems that basically a couple of capacitors are all thats required to start the motor in the correct direction, and a couple of capacitors more are used to fill in the valleys on the third leg. I checked on a rotor phase adder and one appeared to cost approx. $1,400 plus shipping
 
The main motor on the machine says 5.5 kw 380 VAC 50 hz on the nameplate, but the machine has a factory supplied 230 to 380 VAC 3 P transformer which was supplied to supply power to this motor and all other equipment.
 
Question 1 How do I determine what HP 230 VAC motor for the roto-phase adder?
 
Question 2 How do I determine what size capacitors are needed and how many?
 

RE: What do I need

Hi, Wattman.
You might check this document out:

http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

Hope this helps!  Good luck!  LL

RE: What do I need

(OP)
Thanks for the information

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