RPC questions

Tamper84

Active User
Registered
Joined
Oct 6, 2012
Messages
512
Well I do believe I have finally found a lathe, more on that on Friday :D So it's 3 phase and it is also a variable speed machine. So a VFD is out, plus I would like to have a mill in the future which will be 3 phase as well ( well, most likely) I have a buddy and he has a 7.5 horse 3 phase motor :) So does the rpm of the motor matter for building a rpc? Also, we don't know what the motor is valued at, is there a general guideline as to motor price?


Thanks,
Chris
 
Tamper,
the motor rpm is not a factor so long as the rpc is up to speed before you start other equipment.
as far as the value of the motor used probably around $200-300 depending on,general condition,manufacturer, service factor,type,mounting,etc.
just a fyi you are gonna need at least a 50 amp circuit to start the rpc.
I have a 5hp rpc, it starts from a 40amp branch with no issues.
read up on phase balancing,it will save you a lot of money in wasted power.
your power factor will greatly improve through balancing,threfore cost you less to operate
i hope the info helps out.
mike:))
 
Thank you Ulma. I will have to research everything actually lol. I would like to try and build this, but can't find any good right ups on it. Oh I do have a 100 amp circuit for it :)

Thanks,
Chris
 
I'd have to say a used 3 phase motor is worth about $10/HP. Buddy to buddy should be $50 for that motor. Check around a few motor shops or Craigslist. I run a 10hp RPC on a 50 amp ckt.
 
Thank you Ulma. I will have to research everything actually lol. I would like to try and build this, but can't find any good right ups on it. Oh I do have a 100 amp circuit for it :)

Thanks,
Chris

the rpc is really easy to wire up.if you have electrical knowledge, if you don't it is not impossible to do.
if you are interested i can make a posting of my version.
it may take a couple days due to my work schedule, but i'd be happy to assist you if you're not in a rush.
mike:))
 
the rpc is really easy to wire up.if you have electrical knowledge, if you don't it is not impossible to do.
if you are interested i can make a posting of my version.
it may take a couple days due to my work schedule, but i'd be happy to assist you if you're not in a rush.
mike:))
That would be awesome if you could!!! I got plenty of time!!! Thank you!!!

Thank you,
Chris
 
A little update. Went down to my buddy's house after work. Scored a 7.5 horse 3 phase motor and a couple of recessed lights for 30 bucks. But the motor is 3740 rpm. Hopefully wont be too too noisey.

Thanks,
Chris
 
A little update. Went down to my buddy's house after work. Scored a 7.5 horse 3 phase motor and a couple of recessed lights for 30 bucks. But the motor is 3740 rpm. Hopefully wont be too too noisey.

Thanks,
Chris

sweet score!!
the rpc will run with a slight buzz, until you put a load on it then it will quiet down until the load is switched off.
mike:thinking:
 
Back
Top