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will this wiring scheme for 40 HP RPC work?

madmachinst

Stainless
Joined
Jan 15, 2007
Location
Central FL
I want to pull in single phase wire up this panel. and then send the first breaker ( 2 pole 100 amp) to RPC control panel, wire up Idler motor from the controller and then send wild leg to 3rd phase of pictured panel.
IMG_20200430_150824527_HDR[1].jpg

Here is the main idea in general.

RPC suggestion.jpg

Anyone see a reason that won't work. I need specific answers pertaining to the question, I don't cre how many electrons in a volt or what is the speed of an electron. I need to know if this will or won't work and WHY?

BTW, will be using a southern Phase converter 40 hp HD model.
Thanks guys.
 
Leaving out the message about 6 stations for now. It already looks like the work is done. It's a simple arrangement.

Do you expect to use 120V or 240V AC single phase from the panel, or is it all 240V 3-phase?
A 40 hp motor is on the large side. This is not the first time somebody might think bigger is better.
 
Nope , 100 amps WAY to light...Phil

3-P 40 HP motor "in one CHUNK" as "idler" on singe-phase source?

Actually needs more that 200A, doesn't it?

For the CNC loads "wished-for" in his diagram, I'd pause and get Powerco to install a 400 A split-phase service.

Annnnd some combunation of idlers to total 40 HP. 4 X 10, 3 X 15, 2 X 20.. etc.

Not all eggs in one too-DAMNED-hard-to-start basket.
 
RPC seller told me 2 AWG copper will suffice. I sent him a pic of the power rating sticker on the machine. Its to run a 20hp Mazak. I am just concerned with the feasibility of running parallel from the breaker to start the RPC and then bringing the wild leg back to that breaker.
 
RPC seller told me 2 AWG copper will suffice. I sent him a pic of the power rating sticker on the machine. Its to run a 20hp Mazak. I am just concerned with the feasibility of running parallel from the breaker to start the RPC and then bringing the wild leg back to that breaker.

2 AWG Copper carries a lot of traffic. But you haven't said how it is run, nor how far. So far, you don't seem to have what it takes to supply it with that current, let alone what you REALLY need to run multiple CNC-critter loads all at the same time...so it's kinda "academic".

I said 400A service not because you'll need it ALL, but because it is the next step up from 200A on the standard powerco menu, not 234 A or 322 1/3 A.

Or maybe you just DON'T run (as many..) multiple machines at the same time? Money available - or NOT - has a loud vote.

As to the back-routing?

I looked at doing something similar so as to keep the multi-idler RPC feeds and their loads in the same BIG 3-P panel, a "one-stop" place to sort the whole (rather SMALL) shop - inputs on the left column, outputs on the right.. or wotever..

The panel space was there. There's nothing else ON that breaker pole... but ... too lazy to go and grok the Code. And ... it was more "intuitive" to keep 1-P and 3-P load centers separate... even though.. the conductors end-up commoned, anyway.

Welll. Most things do, actually, yah?

Split phase only has the one "set" of incoming. And then they get "distributed" all over Hell and half of Texas.

But we still separate the load centers for more obvious points of control, and at more easily seen and more quickly REACHED locations. Code likes it that way, in general.

2 panels worth. Well. MORE than two..

Boxes are cheaper than excuses, research, agonizing, discussing, and explanations.

Also safer than forgetful what's-hot and what's-not...f**k-ups. DAMHIKT!
 
RPC seller told me 2 AWG copper will suffice. I sent him a pic of the power rating sticker on the machine. Its to run a 20hp Mazak. I am just concerned with the feasibility of running parallel from the breaker to start the RPC and then bringing the wild leg back to that breaker.

Well, for things like that conduct a test phase. One reason is feasibility. The other is not to commit money, time, & materials too early.

You mean only one 3 - phase breaker?
What is the part number?

The cycling wear pattern will be different on the third wire. Subject to higher potential.
At startup the 3rd wire will not be at potential until a delay has occurred.
I would not think that at start up the breaker will respond that fast. But I'm no breaker expert yet.
This is when I would conduct a test before building something up.

Saying this because you can look up the specifications of your breaker and see what they say about it.
Ok, so if after looking at the spec and everything looks good you proceed.
Some period of time after you thought you were done and that very breaker starts tripping when it shouldn't.

1. If the period of time is months then you might have a uneven wear pattern (so to speak).
2. If the period is years then maybe you can live with that.
3. It's possible your idea will be fine and the breaker has a good life.
 
Praying hurts my knees ...


You're trying to emulate a 3 - phase service with a big heavy bruiser.
Better to down the number of 6 machines unless there a 6 bodies doing work.

That BP shouldn't be more than a 2HP, 5Hp tops.
 
Guys, my main load for the 3 phase is

power plate.jpg

then maybe the CNC BP (3 750 watt servos, coolant pump and spindle running all at once)

Or the BP manual. That is it for all the 3 phase load I have right now.
 
There is no way you're going to run a 61kVA load on a 24kVA (240V, 100A 1~) supply. Not going to happen.

There is TOO a way!

Pumped storage pond. Push water up the mountain 24 X 7 with the 24 KVA service.

Run it back through generators one 8 hour shift a day.

See "Smith Mountain Lake" averaging-out the twin 24 X 7 nukes at Lake Anna- then carrying the just home-from-the-office evening peak. Drops a 26,000 Acre lake as much as eight feet of an evening.

Then the nukes - and whatever else is cheap that hour on the greater US grid - pump it back up for the next go.

Smith Mountain Dam is a marvel of machinery | Smith Mountain Lake Local News | smithmountainlake.com

How much cash d'yah have in the bank?

:D
 
Guys, my main load for the 3 phase is

View attachment 308398

then maybe the CNC BP (3 750 watt servos, coolant pump and spindle running all at once)

Or the BP manual. That is it for all the 3 phase load I have right now.

There is no shame in accepting that you will not be able to go full hog with your CNC. Who cares about that.
How many times are you going all out. I can't remember when I did that last.

Don't do any more finish work until you test whatever it is that you are doing.
 
There is no shame in accepting that you will not be able to go full hog with your CNC. Who cares about that.

WTF are you smoking NOW?

"Can't go full hog?"

Can't even START the RPC. Ergo prolly can't even START the CNC, either!

"Can't go full hog".... is down to staring at a foto of an ignorant ham sandwich ... or a Kardashian gal's massive hams... whilst only drooling?

How does either of those pay the bills?

:(
 
There is TOO a way!

Pumped storage pond. Push water up the mountain 24 X 7 with the 24 KVA service.

Run it back through generators one 8 hour shift a day.

See "Smith Mountain Lake" averaging-out the twin 24 X 7 nukes at Lake Anna- then carrying the just home-from-the-office evening peak. Drops a 26,000 Acre lake as much as eight feet of an evening.

Then the nukes - and whatever else is cheap that hour on the greater US grid - pump it back up for the next go.

Smith Mountain Dam is a marvel of machinery | Smith Mountain Lake Local News | smithmountainlake.com

How much cash d'yah have in the bank?

:D

You and your evening peaks.
They're talking about maybe building a pumped-storage facility to handle a dry year here. Nearly seven gigawatt-months.
 
Here is what I am talking about a thread going wild. I am asking about if it is safe to 'breaker' an RPC off the same breaker panel that the wild leg is going back into and everyone is talking about power consumption blah blah blah. I am not making crankshafts or hydraulic rams for bucket trucks. I am making smaller stuff within max 3" diam. I am not concerned about the amperage because the manufacturer has already told me about that. I need to know if there are any safety issues with looping back to the panel feeding the rpc. That is it. I don't care about hydro generators or fusion power plants or how many amps I am getting, running "full balls or not." I am not building my own RPC. Just wiring it in. At this point I am thinking about sliding this down further in the box

308286d1608647286t-will-wiring-scheme-40-hp-rpc-work-img_20200430_150824527_hdr-1-.jpg

and sticking a 2 pole screw in main breaker in that paralleling the output to RPC and 3 ph mainbreaker
 
So you want to bring single phase into a 3 phase panel on say L1 and L2, then supply the RPC with a 100A breaker connected to L1 and L2 and connect the generated leg back to L3; am I reading that right?

I can't see an obvious reason why it wouldn't work....may not be code compliant.
 
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Yes that is what I would like to do. Don't worry about code right now. I am concerned though as to why Code would have a problem with that. If it is something stupid then I don't care, but if there is a legitimate physical concern then I am all ears. BTW this is how the manuf suggests wiring it on his website.

97c3ebdbfaf5aab6e626a53aa0f3d14b.jpg

Only concern there is that if converter is off then no L1 and L2.
 
So you want to be able to run both single and three phase loads off the same panel? If that's the case, no you really need to have a single phase panel and a 3 phase panel for the RPC output.

What the manufacturer shows has is better because the connected loads will always get proper 3 phase from the RPC.

With what you want to do it would be possible to send the connected loads only 2 of 3 phases when the RPC is off, which would obviously be a bad thing.

I guess if you're the only on operating it, it shouldn't be a problem...at start up you would switch all the breakers off, then fire up the RPC and finally switch the load breakers back on; shutdown would be switch off all loads, then switch off RPC.
 
Not to be the electrical inspector, is it ok to run the feeder wires from the meter base to the panel without a conduit?, its not in Montana...Phil
 








 
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