Three Phase question RPC

[dubliner]

I been in the process of installing an RPC to power a 15hp 3P regen. I ran the single phase from the panel to the RPC cap cabinet, and have to run L1,2 &3 to the Generator motor from the same panel. Theoretically when I start the RPC, I have 3 phase, then I start the regen and thats that. Well I ran L1,2&3 from the Blower to the panel ( forgot that I had to run the three wires to the RPC ) and when I hit the start switch(after turning the breaker on ) the blower started up. I shut it down immediately as I realised I didnt have the 3 ph coming from the generator. So my question is how is the Regen running? Did the cap bank kick start it? do I need the RPC motor? I was confused at the start, but now I'm really confused - I know, I know, get a liscensed electrician, and I will but just wanted to know what the deal was. TIA Neville "Sparky" Stewart

[bleeth]

It will run but not nearly at capacity. You didn't hurt anything. Kind of like running your 220 table saw with 110. It may start but won't run very fast. The main thing about 3-phase is making sure your motor is turning in the correct direction. Always do a quick test starting the motor for a second and turning it off. If it is turning the wrong direction, simply reverse any 2 of the three phase leads at either end. I had a friend who got a licensed electrician to hook up his ne large compressor who forgot to do that test. Compressor burned up in an hour.

[dubliner]

So Dave, if the regen was working in the right direction, then I would just have to get the same result when the RPC was installed or switch the wires? I always thought a 3 phase motor would not start on single phase input. I guess it got a kick form the Cap.bank.

[navigator7]

Was it sorta humming????

Rule of Thumb:

1. Double the size of the phase converter for hard & frequent starting loads
2. Use 50% of the converter's full load current to maintain a 5% voltage balance
3. Size the converter for the single largest starting load
4. Always at least round up to the nearest converter size; even for light loads
5. For CNC applications, double the converter hp and use at least a 7.5 hp Converter.

[bleeth]

That is correct. The fact that it turns in the right firection under single phase doesn't mean it will under triple phase. Getting it moving is starting amps. Running correctly is power.