10hp rpc build help

Hey guys so after reading the rpc build thread I am still a little confused. I have a 10hp idler and I need it to power a 7.5hp lathe and 2hp mill. I couldn't find a 15hp so I'll use one at a time for now. I have 9 caps 8 of them are 50uf 370vac 50/60HZ the other is 60uf 7.5uf 440vac 50/60Hz I also have a single pole relay 3100-15Q108 is it's part number. I have a 40amp disconnect I plan on running as the on of for the rpc than out of the rpc I planned to go to a non fused disconnect then to two fused disconnects one for each machine. What amp breaker should I use from the main panel? What amp disconnects should I use for the machines? Should I use a push button start instead of a 40amp disconnect? Here are pictures
Idler
Lathe
Mill
Caps
Relay

What amp breaker should I use from the main panel?

Click to expand...

breakers are sized to protect the wire not to satisfy device

same with fuses

disconnect as you describe is not for protecting wire so it should be able to handle FLA of the device so 30's on individual machines would do
but if you look at what machine tool builders do they over rate the disconnect by a bunch as a rule

my main concern at this time is your actual understanding of the magic pot you are about to stir and should more study come before messing with the smoke gods

but atta boy for asking questions, that is how you will get where you want to go

So I'll be arbitrary and make a suggestion...

Pull some #2 copper wire from the main panel, use an 80A breaker. At the far end panel, use either a 'subpanel' (panel with no breaker), or a 100Aish 'ordinary' panel... whatever you can find (please don't use a HOMline... the breakers are HOPeless... ). From there, size the wire to suit your total RPC load... that means, all the machines you plan on running. looks like a pair of #8 copper from the subpanel to your RPC. use #10awg inside your RPC control box, and you should be okay for a 10hp total load... you could go to #6 copper from the subpanel, and bump up the internal wiring to a #8 on the two main (240v line) legs that pass through, and the generated will still be fine.

There's no need to overbuild the RPC... if your biggest load is 7.5hp, and you've got a 10hp idler, you'll be fine running both... remember, the power you draw will be corrillated to the amount of load you put on the machine, so unless you're doing heavy hogging on both, you likely won't notice. Furthermore, when an RPC has one load motor running, that load motor's inductance helps BOLSTER the generated-leg voltage, so it makes the whole works 'stiffer'.

As Kevin says, you're dipping toes into a bathtub of knowledge, and some of it can be understood from wrote, but other aspects must be experienced in the making, in order to understand the what-why-how of the RPC. Each motor you use as an idler, is slightly different, as is each load, so it'll take a little experimentation to get a fully functioning unit... but after you've crossed that bridge, you'll understand the RPC concept much better.