3 Phase power (Was: What compressor)

When I moved to my current house in 1999, I had the power company come out. I pointed to the 440 3-phase feeder lines going overhead and asked them why they can't just drop me 3-phase power. They said they could but that my MINIMUM monthly bill would be $2250.

End of that discussion.

Grant

Hey Todd,

I moved here a little over 4 years ago, and I asked the local utility company about getting 3 phase at that time. I could get it at either

I suggest you ask if that is an option you have. I would require you buying a transformer too, to get 110.

Brian Lawson, Bothwell, Ontario.

No transformer required with the 208/120 Y service common for most commercial and many industrial services in the US.

The demand in KW (not KWH ) is the rate that you draw power from them. You are billed for what you use, KWH, and another number for how much you draw at any instant. If you have a motor that draws 50 amps on start up the KW demand will be 50 x 230 volts assuming single phase. Your meter will measure the peak demand for any reading period and will show on the bill as a separate item in addition to the KWH and all the other taxes and crap they add to it. With a 10KW minimum demand your bill will be a minimum of 10KW x the demand rate as set by their tariffs. If you get the service you set your equipment so that only one motor starts at a time and if you can, run only one motor at a time so you dont add the running demand to the startup demand of the second motor and bump up the total demand.

They justify demand billing by the fact that they have to have equipment that will handle the peak load not the average load and the high peak rate requires heavier equipment on their end.

John

This is a very good reason to use VFDs on your big motors even though you have real three phase service, the soft start settings can help keep your peaks and therefore your demand rate down.

Now you're starting to piss me off. First you get a great three phase compressor and NOW you can get real three phase. Man oh man, I need real three phase in the worst way, but its miles from me.

Karl

Hi Karl

You already *are* getting it in the worst way.

Don't feel too bad. No guarantee I can get it, and my wife has told me no more money spent on it for at least a few months.... Oh well, time to get the shop organized. I'll still have them look at it, but I may have to wait to get it installed...assuming I can get it at all.

Have you actually moved that huge compressor? Any new pix?

(snip)

Nope, scheduled to pick it up this Friday evening. I should get some pics then. Todd

Interesting. I am also going to be moving a compressor this Sunday, if all goes as planned. Do you know how much your compressor weighs,

Ignoramus6186 wrote: (snip)

According to the literature with a 20 HP motor on it, it weighs 2,010 lbs. A rather cosmic moving experience I would guess.

I moved a Mori Seki LS-6 lathe Friday.

Not that big a deal. Shrug Id guess it was only around 18,000 lbs.

Put power on it today. 76KW at 220vts So I ran 440 to a transformer and stepped it down. That way I could get away with using a 90 amp 440 breaker

Gunner

It's nice to have. All three of my residential shops (since 1967) have had three phase delta 240 volt service. Two of them cost me nothing but signing a contract to consume power. Third one was installed for a distance of greater than 2 miles, but the line was being rebuilt anyway, so all I had to pay for was the third conductor. Could be you could get in on a sweetheart deal like that.

Harold

...

...

Bet you moved it on the back of that pickup that you just installed the helper springs for

Karl

Randy wrote: (snip)

That is my power company and that was exactly the information I needed! Did you have to buy your own meter, or was that included? I've heard different things, but I'm at the edge PPL's service area and PECO's, so it may be different companies. Yeah, I'll be glad to run it all out to make sure I don't have to pay the install charges!

Thank you! Todd

No option to run run the machine at 440v? At 50 HP I would hope that was an option.

Smaller wire = good, copper = expensive

Thank You, Randy

Remove 333 from email address to reply.

I can only speak for the PPL power company in Allentown PA. I got three phase two years ago when I added my CNC machine. (120/240 volt open delta)

PPL uses your peak load for a 15 minute period to determine KW demand. Those few short seconds of motor starting have little to no effect. The only time I ever exceeded 10KW demand was while air-arc gouging out welds, Welder running 350 amp output with 5HP compressor going non-stop.

PPL will provide free hookup to 3ph if your demand is over 10 KW for 3 consecutive months. Worthwhile, IMHO, to run everything you got for

In my case the power was there and the transformers were already on the pole just down the street for my neighbor, PPL just needed a bunch of quad-plex wire.

Even when I had single phase I still had a demand meter since I was a non-residential customer. If you don't have a meter that measures demand I don't think you have any way to even guess what your demand load is.

see rule #2 d (page 7)

HTH.

Thank You, Randy

Remove 333 from email address to reply.

Nah...I used a 20,000 lb forklift and mice

Gunner