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The is a rotary phase converter question

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Alphawolf45:
 Likely not the correct category to ask this but-- I have ordered a 20 hp rotary phase converter to power my big sinker EDM as it was trying to kill my 5hp rpc … But long range plan is to buy a second 20 hp rpc to team with this one to feed the minimum required amps to my plastic injection molding machine that has sat unused since I got it.. The question then is how to wire two RPCs outputs together to get the phases synced ?
     I would have real 3 phase brought into the shop but have fought off cancer and think I may not live long enough to justify a big price tag for two service poles and transformers , 3 phase panel and all else. I am just doing this work for fun and side money to finance the fun.

awemawson:
I'm sure that it must be possible, but personally I wouldn't countenance trying to parallel two RPC's. 
I have a feeling that it would be far too easy to let the magic smoke out  :bugeye:

Why not just dedicate one to one machine and the other to the other?

Alphawolf45:
 Awesomeman  There is as you know a lot of bullhockey on the net . From the stuff I read , if you need 40hp rotary phase converter then two 20 hp RPCs gives an advantage in starting them up..Start one at a time and the surge current is more easily managed.

  20hp RPC will not run the plastic injection molding machine...Even 40 hp total is pushing it...The molding machine is rated at 150 amps full load . Fortunately the motors on the machine never operate all at the same time.

awemawson:
I've made several static phase converters, including an extremely big one, but have only ever bought Transwave commercial rotary ones. Firstly  I had a 3 kW static one that I used to power my Bridgeport Mill, and Colchester Student lathe. Then I bought a Transwave 5 kW rotary to run the whole workshop, then a 15 kW one to run the  10 kW chiller unit for my 100 kW induction furnace (furnace ran off a  generator).

All the commercial ones managed their own start up sequences, and there was no need to interfere. (Though I did once manage to blow the 100 amp 240 volt company fuse with too much running at once)

When I was running off static converters the trick to starting big machines was to have a large (or several large) unloaded motors run up to speed before trying to start the machine in question

Amusingly my first really big static that I made, which was to run my Bridgeport Moog Hydropoint 1000 NC mill and it's huge compressor, I sold to the late Tim Leech (of Dutton Dock fame) and then later saw it advertised on eBay  :lol:

vintageandclassicrepairs:
Hi Alpha,
Not knowing whether you live in an urban or rural location may render my suggestion useless ??
The price of two 20hp RPC's is not to be sneezed at !!!
Would a diesel generator be an alternative ? if it is not to be run full time it should be economical enough.
They come up secondhand regularly

I do not think its very feasible to parallel 2 RPC's
Unless you could split the electrical load between them ?

John

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