ECN Forum Forums Code Related Discussion NEC & other Code issues long run farm pump??

Hey everyone happy holidays,
I have a farmer who is installing a pump 7.5hp electric maybe 5hp to fill his pond from near buy creek 2,000ft away The poco will build a line and xfmer for 5,000.00 dollars he ask me if there`s a cheaper alternative so I`m posing the question here any help.There`s only single phase line avalible at his location 240 volts.I ask why do a electric pump vs engine driven he says running 24/7 he has good luck with electric.
Thanks for your input on this.

RB,
i would think less than 5K would buy a fair genny set-up......

How much water does he need?
By me I've heard that people can sometimes get a pool filled up with the help of the local Fire dept (and maybe a donation).

Bill

Came up with 750kcmil aluminum for a 1ø 240V 4000-foot-total {2x2000} loop sized at 3% running ΔV@0.90PF and 15% starting ΔV@0.30PF

Used Franklin Electric "assumed typical" online data

Calculated using IEEE short method for voltage drop [basic trig—Red Book]

If you’d like to check my figures, email me. I can send a link to an very-slightly-commented .xls [motor links included] file. {Sorry—it’s not intended as tutorial material…some trig functions used.}


—Bjarn

If you can come up with a couple of single phase trnsformers, you can bump the supply voltage up to 480 volts. Then you could get by with 1/0 aluminum. My calculation does not take starting current into account.

Tom

Thanks for the replys.The pump is to fill an irrigation pond that tends to go dry in summer this pump would run 24/7 to keep the pond up.Genset wouldn`t be good choice because of fuel and maint.over long run.Tom I`m interested in your idea but if I boost to 480 volts would i need phase converter can`t locate 480 single phase motor.If so how much would that cost.I was thinking of a inverter I`d still run into the money.Guess thats something not many farmers are blessed with.Thanks Bjarn i`m doing price check on the wire.

I should have been a little more clear. Step up to 480 to send the power to the pond, when you get there, use another transformer to step back down to 240.

480 single phase motors are available, I've seen them in the oilfields around here. Probably hard to find though.

No matter what route you take, this is going to be an expensive project.

Tom

Some "heads-up" points on transformers...be aware that:

You can't use the usual “1 horsepower = 1 kVA” rule-of-thumb for smaller {1ø} motors. To check, mutliply nameplate current by line voltage.

Transformers have their own internal voltage drop...at this range, expect to see 3-5% drop across each at rated kVA. That’s what’s meant by transformer “impedance” or “impedance volts.” Taps come in handy here.

He might try www.capsolar.com as a last resort. I don't know how many gpm he requires but he might could get several and tie them together.