Phase perfect

[RandallsRaceShop]

Which model is that? Unfortunately where the lathe needs to go is right near the electrical service so the phase perfect will be close.

 

[Beckerkumm]

The older models made a sound like sizzling bacon that i could only hear when wearing my hearing aids. Those with better hearing needed to stand close to be annoyed. The lower end models seem to be louder but so is an RPC. Given the cost, I'd buy the size that i could support with my available input input amperage .

Dave

 

[keeena]

I have a 15hp American Rotary RPC going to / 3ph panel. It works great, but I hate the noise of the idler and that it's racking up your electric bill even when your equipment isn't actively running. To be fair, my setup has a user-supplied idler which seems quite a bit louder than the OEM idler (those seem more reasonable in the videos I've seen online).

I like the idea of a solid state 3-phase and have often considered switching. They do have a electronic noise and a fan noise. I don't know many details because I don't have one...only came across this as I was interested in buying one. I have heard the sizzling bacon description as well as a high-pitched squealing noise for other models. I attached video of both. Certainly worth mounting away from your work area IMO; they do have a remote switch option.

 

[Jsd245]

Yeah that does sound fairly annoying. I guess I could just put hearing protection on if it annoys me.

 

[GT-6 Racer]

I'm considering a PP for my next shop - needing a similar load and multiple machines as your +/-20hp. I would do a separate 3ph panel as you suggested. Is there a reason you think the rotary is better than the PP at this scale/use? Not familiar with VMC. I don't currently have a full size wood cnc, but its likely in the future. Any reason to up size a PP for that (potential future) load vs just getting another separate 3ph system for that entire setup? It would be a big jump in the load without an immediate, or potentially ever use.

The big thing was cost for me. I looked at PP but the cost was substantially for the higher load systems. my system AD-20 (10 HP start) is about 2900$ now. The cheapest PP system is about 3200$ for a 10HP start is the PTO10 (the PP is a little higher 3 phase Amps at same HP rating). However, to get the same multiple load amps you need to go up to the 20 HP size PTO20 which is $7700. This is the way I understand it ( definitely need to talk to the vendors with your data. So, if simultaneous loads are the norm, the PP is much more expensive. If a single big starting load is the norm then maybe price differential is less. I have the outdoor idler, indoor panel. I highly recommend the idler outside due to noise. I had it inside for a while and it was the loudest thing other than the air compressor. Very annoying. The cost to run idle is on the order of 3-5 cents per hour so not much, 50 cents a shop day is the least of my expenses. If you were all day 50 weeks a year as a business maybe it's more a significant cost. Both systems will require capacitor replacement occasionally. If i had unlimited funding, I'd just have 3 phase utility ran, but 60K was the quote... way out of bounds, since I don't have Elon levels of dough, the digital rotary seemed to me to be the right choice even for CNC machines.

 

[rwm]

The answer is so obvious. Just cook bacon while you're running it.

 

[GT-6 Racer]

The answer is so obvious. Just cook bacon while you're running it.

Mmm bacon

 

[Beckerkumm]

There is a used 10 hp PP for sale on the Practical Machinist site. Dave

 

[Eddyde]

I have a friend who has a PP he spent thousands on and isn't thrilled with it as it generates a stinger phase, 240v to neutral, this made it tricky to set up his CNC machines as the stinger can't be used with the electronics. This necessitated careful tracing of the machines circuits to insure that leg wasn't used for powering the electronics.

I built a 7.5 hp RPC for less than $400, it works fine and is hooked up to a 3 phase panel for distribution. It doesn't have a stinger phase but the generated phase also shouldn't be used to power any electronics, though that isn't and issue for me as I don't have any electronic controls on my machines.

 

[Beckerkumm]

Define stinger phase. All high leg delta converters, generate a high voltage leg. The PP measures 208 to ground ( which is correct ) while an RPC leg can very significantly . If the RPC is perfectly balanced, the high leg will still be 208 to ground. If the PP is measuring 240 to ground on the manufactured phase, something is wrong.

Dave