Wiring up a 30HP rotary phase converter

[Oscar]

You stole the wire for sure. Good deal man.

What are you pulling for a ground ?

You running it in some EMT, PVC or Greenfield/Flex ?

All very good questions that I need to ponder. I'm gonna re-think the whole scenario for the garage. I'm thinking metallic flex might be the most robust. I need to unwind this thing first thing tomorrow morning.

[Robb M.]

test post

[Oscar]

Now it works, thanks Robb!

[Oscar]

1/0 and 100A breaker should work just fine. I ran a 30hp RPC on a similar sized breaker for years.

Ditto Daniel's advice for using a panel instead of a single breaker enclosure. With a panel you have the ability to easily add additional 3 phase equipment. Frequently you can find a better deal on 3 phase equipment as opposed to single phase because fewer people have the power to use it.

On your 30HP RPC, how much amperage did it consume at start-up? How about once running, yet unloaded with any equipment? Ever measure it to see actual numbers?

[Oscar]

36 bucks for 120 feet of 2/0 is a steal.

Just measured it. 120ft indeed.

[TraditionalToolworks]

Just measured it. 120ft indeed.

Nice score, I'll say that! Whether it fits your needs here or not, I'm sure you'll find a use for it.

EDIT: I should add, I'm not electrician and have never claimed to be. I suspect that will be fine if he talked to the vendor, but again I'm not an electrician. Sometimes a lot of drama on the Internet.

[scsmith42]

On your 30HP RPC, how much amperage did it consume at start-up? How about once running, yet unloaded with any equipment? Ever measure it to see actual numbers?

I have a transfer switch with meters on it at the service entrance to my shop. It's an older model, and the meters can probably use a good cleaning, but it's representative. Attached is a video showing the current inrush when starting my current 40hp RPC, and the second inrush when I start a 10hp 3 phase air compressor that is fed by the RPC.

The inrush when starting the RPC is well in excess of 100A. You can tell by how hard the needles slam the stop. My former 30hp RPC also would demand well over 100A when starting.

[Oscar]

I have a transfer switch with meters on it at the service entrance to my shop. It's an older model, and the meters can probably use a good cleaning, but it's representative. Attached is a video showing the current inrush when starting my current 40hp RPC, and the second inrush when I start a 10hp 3 phase air compressor that is fed by the RPC.

The inrush when starting the RPC is well in excess of 100A. You can tell by how hard the needles slam the stop. My former 30hp RPC also would demand well over 100A when starting.

What size wire and what length do you have feeding the 40HP RPC?

[Jawslandshark]

Mine hits 99 amps on the digital meter for starting inrush on the 30hp.

Oscar I have to try and push this to at least 5 pages!

[Oscar]

Mine hits 99 amps on the digital meter for starting inrush on the 30hp.

Oscar I have to try and push this to at least 5 pages!

You know you can condense the # of pages by going into your settings, right? lol

What size wire and what length do you have feeding your RPC panel?

[scsmith42]

What size wire and what length do you have feeding the 40HP RPC?

Length is less than 10' from single phase breaker to the RPC. As I recall wiring is 1AWG but I'd have to double check it.

[Oscar]

Length is less than 10' from single phase breaker to the RPC. As I recall wiring is 1AWG but I'd have to double check it.

Thanks. I'm just getting a feel for what I will be dealing with.

[Steve from SoCal]

Oscar,

Do you have any idea the size and number of houses on the transformer you are getting power from? A number of power companies have a stipulation in residential service about starting any motor over 10HP without calling them.

[TraditionalToolworks]

Oscar,

Do you have any idea the size and number of houses on the transformer you are getting power from? A number of power companies have a stipulation in residential service about starting any motor over 10HP without calling them.

Steve,

That's interesting, I haven't heard that...but I know the shop/home I'm building has 4 houses on each transformer I'm told. I'm the 4th of the service I'm getting hooked up so I only need to pay $75 hookup fee. I could have had 3 phase from the pole, but they wanted me to pay $15k for the transformer...where a 320 amp transformer is free.

Curious, per your sig it would appear you're in KS fulltime now? Weren't you in Woodland Hills area before? I can understand getting out of California, the left is doing it's best to destroy it...

I grew up in the SF Valley.

[Steve from SoCal]

Steve,

That's interesting, I haven't heard that...but I know the shop/home I'm building has 4 houses on each transformer I'm told. I'm the 4th of the service I'm getting hooked up so I only need to pay $75 hookup fee. I could have had 3 phase from the pole, but they wanted me to pay $15k for the transformer...where a 320 amp transformer is free.

Curious, per your sig it would appear you're in KS fulltime now? Weren't you in Woodland Hills area before? I can understand getting out of California, the left is doing it's best to destroy it...

I grew up in the SF Valley.

I still have my house in Woodland Hills, haven't spent much time there the last few years. I could never have the shop I do in California at least not near anything.
While there are some crazy things California is home and I still long to see the mountains and beach.

[Oscar]

Oscar,

Do you have any idea the size and number of houses on the transformer you are getting power from? A number of power companies have a stipulation in residential service about starting any motor over 10HP without calling them.

No, but I guess I'll find out when they come'a knockin!

[TraditionalToolworks]

I still have my house in Woodland Hills, haven't spent much time there the last few years. I could never have the shop I do in California at least not near anything.
While there are some crazy things California is home and I still long to see the mountains and beach.

For better or worse I'm staying in California as I have a piece of property up in Lake County I'm building on. Not as spacious as I would like but will have more space than I do where I live and only have 1/2 the garage for my shop. I hope to build a detached 30'x40' shop after, but shop is going in my basement to build the home.

Power is a huge issue, Oscar seems pretty lucky as he has quite a bit of power. My current home is only 125 amps and I run the entire shop on a 30 amp converted dryer circuit along with a 20 amp 120v.

I have a Phase Perfect PT355 (20HP) for the new shop, it's getting a 320 amp circuit.

I'm kind of surprised to see how difficult it seems to setup the RPC, my plan is to run a 100 amp breaker for my Phase Perfect and have it going into a small 3 phase panel to feed all the machines.

I use extensions and plugs for everything now, going to the RPC or single phase it plugs into, but want everything on it's own receptacle in the new shop. I want everything in it's place so I can just flip the switch and run them. I only run one machine at a time for the most part, but in the future could run dust collection along with another 3 phase machine.

I really don't even want to know how big your shop is in KS, would be tight for me to get even one of your Monarchs in my new shop, which will be mostly woodworking machines to start. Do you have 3 phase to your shop in KS? (go ahead, make me sick )

EDIT: on that 10HP motor limit, was that true in Woodland Hills? That's SoCal Edison down there, isn't it?

[Oscar]

It's not that difficult I suppose, but I do like to cover my bases from all angles when I'm not sure. As for my power, electricity is pretty reliable here. Time will tell.

What is interesting is that the vendor suggests an 80A breaker and 4awg wire is all that is needed for this RPC.

I mean, I'm still gonna use the 2/0 wire that I got since that will minimize the voltage drop. But it seems everyone is running these on 100A breakers.

[Steve from SoCal]

I feel for you guys, I do. When I had my shop in my garage in Woodland Hills I had all the same issues.

About the shop in Kansas, it is kinda bits and pieces. The oldest parts are from the mid 1930's about 9K sq ft, the metal buildings are about 25K, I demoed a 6K part due to freeze damage. I do have three phase, 600 amps 480 with my own transformers for 240/120. I ain't all wine and roses, demand charges and fees are pricey.

Traditional,

It is LADWP and yes, Edison as well AFAIK

[Oscar]

Spend all day upgrading wiring with 2/0. Absolutely hated it. Still need to run more wiring but the worst is done. Waiting on breakers.

[danielplace]

Spend all day upgrading wiring with 2/0. Absolutely hated it. Still need to run more wiring but the worst is done. Waiting on breakers.

Just a heads up.

The 2/0 wire is a problem instead of a bargain looks like.


The BR2100 is only capable of accepting 1/0. Most likely 2/0 won't physically fit either. The RPC panel lugs are probably alright.

The BR2125 is rated to 2/0.

Not sure what your best route is here now.

#1 Go buy the proper size wire.

#2 Polaris tap to something smaller.

#3 Clip some strands. WTF !!!

#1 being the best route of course.
#2 Cost of the taps and just the idea of using them for this.
#3 Surely not the right thing to do but absolutely would not hurt one iota just at the end to get it in the breaker.

Hope and pray you get lucky and it will just make it in the hole of the BR2100. Take a piece of that 2/0 with you with the end stripped back a little for a test fit then decide the cure. Maybe the Dremel and you could carefully enlarge the opening slightly if the meat is there.

[Oscar]

I did end up ordering BR2125 breakers. The subpanel will feed that little breaker box remember, the 1-Φ 240 Eaton I posted. Then from there I will route power to the RPC panel.

[danielplace]

I did end up ordering BR2125 breakers. The subpanel will feed that little breaker box remember, the 1-Φ 240 Eaton I posted. Then from there I will route power to the RPC panel.

I thought you were already feeding from a subpanel from the main panel that is main lug only straight from the meter. Can't trip that on startup. Might be a plus with that working in your favor.

I remember the 3 phase breaker enclosure on load side of RPC. Missed the single phase one on line side of RPC.

So you are feeding out of that subpanel to disconnect before the RPC. I didn't realize, pickup on that detail or forgot.
Somehow I was thinking you were coming out of a subpanel that was only fed with a 100 on a 100 BR2100 and then the rpc. I think it has been a few days and I may be confusing your details with another thread.

You put that in to have an easily accessible RPC switch instead of switching breaker in panel. I see. Cool.

[Oscar]

Yes, I think you outlined it correctly. I think I hadn't updated the info about me getting the BR2125's.

[scsmith42]

Spend all day upgrading wiring with 2/0. Absolutely hated it. Still need to run more wiring but the worst is done. Waiting on breakers.

I feel your pain. A couple of weeks ago I installed a new triple head wide belt sander into the shop. 103 total HP. Had to pull three 3/0 wires with a ground through 90' of existing under-slab conduit to feed it. What a joy that was when the wire reached the elbows...