Power Issue with my Machine Shop

Gunner wrote:


Did they tell you why?
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John R. Carroll
Machining Solution Software, Inc.
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on Thu, 23 Nov 2006 18:21:13 GMT in rec.crafts.metalworking :

    "we don't need a reason, we are the Power Company. We are Om-nip-otent." Thanks to Lily Thomlin's "Ernistine, the Telephone Lady."
tschus pyotr
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pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
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On Thu, 23 Nov 2006 21:37:15 GMT, pyotr filipivich

It's a bit like getting Oxy Acelelene tanks. You are paying for the 3 phase line and transformer and its maintenance, which changes very little between 100 wh per month and 500kwh per month. You could, of cource, pay to have the line installed, and buy the transformer. Then it might cost you $100 per month instead.
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Nope..just lots of wheel spining and blinking.
Gunner
Political Correctness
A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
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The guy at REA told me it was because of the extra money needed to run and 'up keep' 3 phase lines. IIRC, he said one of the extra cost was the fact that even if 3 phase was running near me I'd have to have more than one transformer (3 pops into my mind) installed
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That's partly a Red Herring - they send the main 'trunk feed; for the area as 3-phase to keep the powerplant generator loads even on all three phases - Power is almost always generated and transmitted as 3-Phase.
If you live right along the main trunk-line feeder route, it's already up there. Go out and look at the top arm of the pole right outside your house, it will have either three or four conductors on the top arm - if there are four, one is on smaller (often white) insulators and that's the ground leg.
(There will be "butt plate grounds" and grounding risers spaced every few poles.)
Now if you live on a branch to the main feeder, where they only brought two hot legs down for a Delta-fed transformer (or one hot line and a ground lead for a Wye-fed transformer) they *will* have to extend all three hot lines to the pole outside your house or shop. But that doesn't cost them all that much.
You can guesstimate the cost - drive out to the main road till you see where they catch all three phases, and then watch your odometer on the way back to get the distance, and count the poles along the way. Your utility can give you the cost per mile figures.
You only need two transformers on the pole to get a 120/240V Open Delta feed - The existing one stays for the regular loads and they add a small can to get the Wild Leg. But it takes three transformers for a full 120/240V Delta or 120/208V Wye.
The lower voltage 120/240V Open Delta feed can be a pain if you want to run big motors - but it also allows them to feed your house and other houses 120/240V single-phase loads off the same transformer set.
If you want 277/480V Delta they leave the original 120/240V 1ph transformer and hang a new set of three above it for the 480V. And you get stuck with the demand charges - it costs money simply to energize the transformers even if they are not heavily loaded.
The Co-Op or Public Owned utilities price that work out simply to break even, but for some strange reason the "For Profit" utilities usually charge more...
(And don't sweat minor details that are "wrong" for your area - each utility does their thing just a little different.)
--<< Bruce >>--
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I live in the middle of no where, it took them almost 3 weeks before the powers that be could even tell me what my mailing address would be. Does that tell you how far it probably is to the main trunk line?
As it stands right now I can't afford to buy used equipment much less build a shop to put it in so the cost of getting 3 phase is way down on my list.
<good stuff cut>
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"Bruce L. Bergman" wrote:

For three phase you will only need two hot lines on the pole.. the ones at the top of the pole with the big insulators. They can give you open delta but thats still better than a phase converter. In phase realtion to groung the two hot wires are 120 degrees apart. The delta output from the two transformers consists of three wires, the paired connection of each winding and the other two ends of the two windings.
John
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on Thu, 23 Nov 2006 18:16:26 GMT in rec.crafts.metalworking :

    Makes a genset of your own a viable option. I mean $500 a month will cover how big a generator? According to my catalogue here: 8kw 100 amp standby generator for $3000 (plus shipping and handling, it costs to get those fingerprints put on). Eight to nine months and you've got that paid for.
    But I'm sure that Gunner can get you a "deal".
pyotr
"Such a deal I got for you, I wouldn't give my own brother. But then he knows where I live."
--
pyotr filipivich.
as an explaination for the decline in the US's tech edge, James
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We used to rent warehouse space in an old furniture factory that had three phase. The only thing it ran were a couple of fluorescent light (most of the bulbs were burned out or broken ) for about 5 hours a month.
Every we got a bill for $80.00 with the description "In Lieu of Demand"
I miss the warehouse, but I sure don't miss that bill.
Paul K. Dickman
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wrote:

What a ripoff, my second house had 3 phase power at no extra cost for the meter, the third cost an extra $200 for the 3 phase meter as the peak draw was 25 kW, mainly electric stove & oven + 5 kW aircon. Regret moving. Current house also has 3 phase, which I need to get extended out to the shed. Long power cords are a PITA. Residential does not attract a peak loading charge. Cannot find latest account, it was about $120 for winter, (Aug/Sep) last one for old house was $194.45 for 58 days, (Jan/Feb) aircon running part of most days, but it was a cool summer.. Cost per unit is 13.94 cents, receive account every 2 months. Just had 3 smaller aircons installed instead of 1 large one, ready for summer. Warm yesterday, about 95F, cooler today, only 85F. Alan, in Gosnells, Western Oz. VK6 YAB VKS 737 - W 6174
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On Sat, 25 Nov 2006 00:13:45 +0800, snipped-for-privacy@iinet.net.oz wrote:

Up here on the "top" of the world, residential 3 phase is almost unheard of (at leas in North America - particularly Canda.
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Carbonite wrote:

When you turn on an electric motor, its starting current is momentarily larger than its running current, even loaded. All wire has resistance. The large current running through the wire resistance causes a momentary droop of voltage, which is what causes the lights to dim briefly.
You could go talk to your neighbors and explain to them that you're just turning on an electric motor. If your relationship with them is good, and if you help them fix things from time to time, maybe you can solve this problem politically; i.e. just by talking.
You could also maybe switch to a rotary converter with power factor correction capacitors installed. You can't do much about starting current in your mill's motor, but at least this way you can reduce the reactive current in the line, all of which contributes to the perceived voltage drop.
GWE
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Carbonite wrote:

So call the power company and ask!
Since you have not supplied a location, or the name of the power company, there is little chance of getting usefull information from any other source.
You may get lucky and the Power Co will upgrade your supply for no cost, as it appears they have already done with the transformer, or they may tell you that you are getting as good as the supply line is capable of, in which case I would be looking at three phase motors, Variable Frequency Drives (aka VFD's), and programming in a soft start , so that the surge does not take down the neighbors power.
Cheers Trevor Jones
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5 kVa service??? That you share with your neighbors???????????

I would just get a variable frequency drive. It is much nicer in regards to starting and running those motors, as far as starting surges are concerned.
i
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Ignoramus8450 wrote:

In all probability that was supposed to be 15 kva. Remember also that these utility grade transformers are rated to handle a 100% overload for 24 hours without damage.
If the OP is really out in the country the problem may be in the primary distribution lines out to his area and not in the local transformer. Indeed if a Bridgeport of what, 2 hp starting up is causing a noticeable dip after the transformer was upgraded to 25 kva this is likely the case.
The utility isn't likely going to replace the miles of primary until they are convinced it is old enough that's it's become more costly to repair than replace, or some big customer comes into the area like a big commercial building or a big housing developer.
Pete C.
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I'm not an expert or anything but it should be pretty easy to rig up a UPS unit to feed enough power to get past the initial current ramp on those motors- I can't vouch for your area but I know around here almost every junkyard has several large UPSs that you can buy by the pound. The trick will be matching your discharge curve to that initial spike- you'd need a much larger unit than rated for those motors because they draw so much current cold. Beyond that though it shouldn't be a problem- just make sure that you're primed before you turn the whole setup on.
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My 10 HP idler motor draws about 120 amps of 240v at startup. That adds to about 28 kVa. Very serious size for a UPS, it would weigh about a ton. It would also have enough electronics to salvage to afford to buy a small VFD for the bridgeport mill.
i
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Ignoramus8450 wrote:

Right, you have to get a big (free) three phase online type UPS and modify it to provide you with "real" three phase power for the shop complete with starting surges, while drawing a nice constant load of single phase from the utility and even keeping you from wrecking parts you're working on when the utility power goes out.
Pete C.
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Yep, good point about those giant UPSes being 3 phase.
i
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