triping circuit breaker


no
I've got a large RPC for my 20 hp lathe. It really bogs the whole place down when starting the lathe with no load. A pump is actually under INCREASED load at startup (no water pressure in lines - pump tries to lift it all at once). I'm very doubtful this would work.
Karl
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Karl Townsend wrote:

On a pump with a constant load you could use a start run cap setup like you would with a rotary converter but without the extra motor. Since the load is constant you don't need an idler motor but you would have to figure out the amount of run caps to get the proper phase shift at the current draws you are getting. The idler motor only is necessary if your load varies a lot otherwise the caps will work fine. Its the same thing as a single phase motor with start/run caps.
John
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Hi Karl
I guess you wont mind a top post for this question. I only want to know the size of the RPC you are using to run the lathe.
Jerry

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On Sun, 08 Jul 2007 13:00:18 GMT, "Karl Townsend"

NO! No phase converters! And you REALLY don't want to try boosting 240V to 480V with a transformer, you need a 480V service.
Your friendly neighborhood power company will gladly install a separate 3-phase service for you if you have a legit need for one where single-phase won't cut it - and a "Well Service" certainly qualifies. Might even get a better power rate for that service.
Call up your well people first thing Monday morning, and see what your voltage options are on the pumps. Then call the power utility and ask for a 'meter spotter' or 'service planner' (or "Ted in Engineering" if it's a small outfit) to come out and do a site survey.
See what they will give you (240V or 480V) and the maximum amperage they'll install without requiring engineered blueprints, and where they want the equipment mounted /before/ you start calling contractors.
You hang out here, so I'm pretty sure you know which end of a wrench goes on the bolt... ;-P You can probably do it yourself (and some of the ranch hands) as long as the local building inspector is willing to work with you, it isn't brain surgery.
(I seem to recall a project involving a total rebuild of the apple packing line and engineering new rubber sorting cups...)
They have pre-packaged wellhead panels (fused disconnect, starter and overload, and Warrick safety cut-offs if the well runs dry) that the well guys can get and mount on a backboard next to the wellhead - you just have to supply 3-phase power out there.
The simplest and cheapest way is to hang a one-piece 100A "Meter Main" on the backboard next to the well (one post of the backboard is a 20-footer for the service mast), place a mast and a ground rod, and you're done. Call for inspection, and when you pass the utility hangs new transformers and heats it up - but that doesn't solve the problem of the lathe and other 3-Phase loads in the packing barn or shop.
You might be able to get away with a simple 200A service at the well, then run it back to the barn later, but that's bass-ackward. The well loads are fairly fixed, but the shop loads will grow.
Put the 3-Phase service panel at the main barn. One circuit out to the well, the others go inside to the lathe and other things. Toss the Rotary Phase Converter and give them real 480V 3Ph.
Look up "Instant Service Switchboards" - they come pre-packaged and ready to go, 200A - 400A - 600A at 240V or 480V 3Ph. It's a ~32" wide standing section cabinet with the meter socket and current transformer mountings on top, main breaker or fused disconnect in the middle, and on the bottom a distribution breaker section. If it's underground fed service there's a second cabinet to one side for the landing lugs. And they have Raintight units if you don't want it inside - just pour a slab and plop it down.
And service sections are available used, they get salvaged when an almost new building gets torn down or remodeled for a new tenant with different power needs - there are electrical equipment brokers that buy and sell them just like junkyards. It might have a few conduit holes you have to plug, big whoop.
--<< Bruce >>--
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...
i WISH i could get real three phase. The closest three phase power line is three miles away. Other shops around here have had estimates of $20K per mile to pipe it in. Not going to happen.
Is the VFD option with single phase input also not workable?
I'll check every irrigation well outfit to see if I can get another 15 horse 1 phase pump or get the one I own rebuilt.
Karl
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On Sun, 08 Jul 2007 22:11:02 GMT, "Karl Townsend"

Don't go defeatist on me yet - you haven't really tried. ;-P As the Old Philosopher said "Never give up, Never Give Up that Ship!"
http://www.search.com/reference/Eddie_Lawrence
When the mere mention of your name in the Power Company executive board room is met with curses and derision, THEN you can say you've tried. You have reached the people with the power to say Yes and make it happen, and if they still said No you made life uncomfortable for them for a while. And yes, now they know your name.

You can do it that way, but the extra conversion losses in the VFD are going to cost you. The only way a VFD would make sense is if you were going to vary the pump RPM to match the water flow and pressure you need, and save power making extra pressure you don't need. Could be done, but it violates the 'Rule of KISS.'
Not to mention the well pump motors have to be designed and nameplate rated for "Inverter Duty", and for submersible pumps that aren't normally run on a VFD I doubt they're available. Though stranger things have happened...
Three phase motors are the most efficient way of converting electricity to rotational work performed, period. But if you have to manufacture that 3-phase with a RPC or VFD, there goes your efficiency.
And for some uses, 3-Ph is a necessity - I have never seen a 1-Ph passenger elevator pump motor yet, real bad things happen if the pump starts backward and (though rare) it can happen on a 1-Ph motor.

Time to start rattling some doorknobs and making a little noise, which might include filing a complaint with the state Public Utilities Commission, or whatever they call the regulation/oversight body. The utility not supplying you with what you need is silly.
Gee, that's precisely why the Rural Electrification Administration (now the USDA-RUS) was formed, because the for-profit utilities wouldn't invest in the outside plant to get the power you need to where it's needed. Find the local office, they might be interested in this problem, too - especially if they financed the line that heads to your farm now with an REA Loan...
http://www.usda.gov/rus /
You are running a business and you need 3-Phase to run heavy motor loads like the well pump properly, and the utility is only fooling themselves if they think they don't have to run that third leg to your site. (One more leg if you are connected Delta - they need two more legs if you are hooked up Wye to ground.)
And if you have other neighbors with shops and farms that also need 3-Ph power for their wells and equipment, go document it. A list of names and expected loads - let the utility break it down into dollars.
They tried asking as individuals over the years, and were turned away - now you need to ask again, but as a proven group of willing buyers. It will strengthen your hand if you can prove enough load exists at the end of that leg to make it worth their while to run it, the power revenue will pay back the cabling investment.
If the utility tries to stonewall or charge a small fortune for the line extension after you prove there's a valid need, that's the time to have a consultation with a lawyer who is familiar with your state's utility laws and processes, state and county regulatory bodies, and the REA/RUS federal policies. Call the state bar, they can find him.
Sometimes all you have to do is call the utility to talk to someone in the President's Office and drop a name to prove you are serious about this ("I'm talking to Joe Lawyer about this tomorrow...") and they'll stop BSing you and shift to "Git 'Er Done" mode.
Even if you get them moving on it right away it will take them a few weeks to do the engineering, order materials, schedule the crews, upgrade the poles and cross-arms where needed, and string the extra wires.... And it'll take you about the same time to get the new service panels ordered, installed and inspected, order the new pump and panel, and have the well guys trip the old pump out and the new pump in.
--<< Bruce >>--
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"Bruce L. Bergman" wrote:

Three phase submersible pumps running on inverter drives are pretty common actually, particularly in solar pumping setups.

I think in this case, reliability trumps absolute efficiency and if the efficiency gains of a three phase pump are canceled by inverter losses it's a wash. I still think three smaller three phase pumps running on three smaller VFDs is the way to go. Should be able to fit three 5HP down the same hole as one 15HP and get triple redundancy and the ability to drop units off-line entirely when water demand is lower.

Have you ever seen any behavior from a utility that wasn't silly?

Sometimes finding a politician who needs a few PR points with the locals for their pending re-election can help.

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If utility three phase power is not available, then a VFD (with proper line reactor that is necessary) and three phase inverter duty pump would seem to be the best approach.
i
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On Mon, 09 Jul 2007 09:13:03 -0500, Ignoramus6542

Yes, it's the best approach with the existing conditions - but Karl hasn't nearly exhausted his options for getting the power company off their asses to deliver 3-Ph yet.
KISS still holds - 3-Ph utility power is still more reliable and efficient than a VFD. The less that can go wrong the better.
--<< Bruce >>--
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On Sun, 08 Jul 2007 13:00:18 GMT, "Karl Townsend"
<snip>

Hi Karl,
My Dad used to dabble with wells and pumps. Have you checked into getting this one gone through/rebuilt? Most of the better quality pumps can be rebuilt. The electrical portion (barring any leaks/corrosion) should be okay. Probably just some bearings, impellers, clean-up and such. Check with the manufacturer and find out who rebuilds/services these in your area. It can't hurt to ask and may save you a bunch of hassle.
As far as going three phase I would be concerned with lightning strikes. Submersible pumps just beg to be zapped by lightning and your expensive VFD running it? That would be one hell of a ground rod attached to a bunch of electronic components... Even if the hit is a few miles away they just love to find there way over to a well to completely dissipate.
--
Leon Fisk
Grand Rapids MI/Zone 5b
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that
Kirchoff says current is equal in a series circuit ...true. Where's the 5 amps going? If the amp meter is reliable then of course one would suspect the breaker ... however , did you check the current rise on the main? If you add the no load to the full load does it agree? Since the unit is outside did you check for oxidation at the main?? At the breaker input? At the supply source? and at the peckerhead? Don't assume anything ..... I once had a large isolation transformer 1-1 ratio meter read almost twice the current in the output then the input. Wattage in always =wattage out. Long story but it did happen
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wrote:

Don't know how much this will help but breakers are thermal trip on the "overcurrent" range. They need to be de-rated in higher ambient temperatures, (which I hear you've been having out there). Square D, (Schneider Electric) publishes figures for this. Allowing convective cooling by removing the box cover should help some. Breakers do wear out, they're not intended to trip too often. Before you go replaceing the unit try as suggested elsewhere to clean both the bus and wire contact surfaces, especially if you've got aluminum cable, check that it has a good firm contact, the stuff tends to 'creap` under thermal cycling and that can cause heating. Best of luck, MadDog
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They do -- but even worse, it seems that after they trip they don't reliably trip at the exact same current the next time.
Consider using fuses instead.
Karl Townsend wrote:

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Karl Townsend wrote:

Get a high efficiency diesel 3 generator (Lister) and a good three phase pump.
John
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when
Pumps
out
that
breaker.
Good Lord!!!! What's next, a hydro-electric
I was senior control designer for Enviro Systems in Southern Florida and have never seen such a wrangle over a single phase pump. In all my years working with YaHoo's and Rednecks I have never heard such ridiculous garbage.
Listen to me dude. The Pump Ran Now the pump doesn't run. Either the power to the pump or the pump itself. Don't redesign it Fix the problem ..it is only one of two things God has not cursed you. ....Geezus !
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So how did it all work out?? It may be nice now but next week is supposed to be HOT and HOTTER.
Karl Townsend wrote:

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