three phase power and alternative energy

davidbullhawley · 03-28-2009, 10:59 AM

I have a deep water well that is wired with three phase power. I want to set it up on wind/solar power. How will three phase affect the set up of my system?

Plumber101 · 03-28-2009, 11:10 AM

How deep is your well?

I have not seen any well pumps in my time set up as 3 phase. I have seen shallow wells on solar supplying water for live stock that has a reservoir. Never seen one for house hold use.

Please provide more details....

J. V. · 03-28-2009, 12:22 PM

You will need a 3 phase pump motor, and you will have to adjust the control circuit for three hot conductors.
I know little if anything about wind or solar power.

micromind · 03-28-2009, 12:51 PM

The well at my house is 120' deep, it has a 1-1/2HP 3 phase submersible pump. They do exist, but are indeed rare.

A 3 phase pump can be operated with a wind/solar system, but cost might be prohibitive. If you can get the wind/solar system to produce enough single-phase power to run the pump, there are basically two ways to run a 3 phase pump this way.

1) A phase converter. Get a rotary one, not a static one. Oversize it a bit. If it's a 2HP pump, get at least a 3HP converter. Submersible pump motors are very sensitive to phase imbalance.

2) A VFD (Variable Frequency Drive). Smaller ones (5HP or less) are available with single-phase input. All VFDs are 3 phase output. Oversize it a bit as well. Control will be a bit more difficult with a VFD. You'll need to set it for 60HZ, and re-connect the pressure switch to the control input of the VFD. A VFD might not like inverted power for its input. Most of them will accept DC input, you'll need make sure that your wind/solar systems DC output matches the VFDs DC input. Most 240 volt VFDs like about 300-350 volts DC.

This certainly can be done, but there's a huge amount of planning and research needed to get it to work.

Rob

jbfan · 03-28-2009, 03:29 PM

Rob, how did you get 3 phase at home?

micromind · 03-28-2009, 05:00 PM

Around here the POCO will connect any size/type of service you ask for. The property zoning doesn't matter.

When I met with the POCO staking engineer at the property, I asked for a 3 phase service, as I had a bunch of shop equipment that was 3 phase. We discussed service location, load, etc., and a few days later I received several price quotes from the POCO. One was for single phase, another for a 240 open delta, a 120/208 wye, they even gave me a quote for 480.

I decided on the 208 wye, paid the fee, got a permit, set a pole and panel, got it inspected, and within a few weeks, they hooked it up.

Their price for connection is based on # of phases, main breaker size, overhead/underground, etc. I could have asked for 4160, they would have hooked it up, but it would have been very expensive!

Rob

joed · 03-28-2009, 06:32 PM

It is sort of simple.
Buy three phase solar and wind generating equipment to match your service needs. It probably costs a lot more than single phase but I'm sure it is out there.

philS · 03-29-2009, 10:42 AM

3 phase solar or wind is no longer a big deal or huge expense. I haven't done it myself but the manuals for my single phase equipment make it sound no more complicated than 120 single phase or 240 2-phase (or split phase as electricians call it). For 120 you can get by with one inverter (unless you need more watts than a single inverter can supply, in which case you run two in parallel), For 240 "split-phase" you run two. For 3-phase you run 3. For all multi-inverter systems you designate one as master and the others automatically become slaves. You then are led through a programming sequence where you pick how you want the slaves configured with respect to the master. 3-phase is one of the options. As I said I haven't done it myself and I don't remember whether you can choose between wye and delta. Also, the above is based on the manual for Outback Power Systems. Things might be different for say Xantrex. Check the Outback site and you can find all the manuals and a user forum where (like this one) folks will be happy to help you though the system design and implementation.

Incidentally it doesn't matter what kind of DC you feed into the inverters - it can be solar, wind, hydro or all 3. And the inverters can be set up as interactive with a 3-phase POCO service if you want, though that adds cost. Cost of the extra low-end inverter is a few $k.