XW inverter questions?

Re: XW inverter questions?

Do you want to run the 3 phase equipment from battery, or just use Grid Tie to "spin your meter backwards"?

If you don't want to run your shop tools from 3 phase battery backed power, any Grid Tied system should work fine (for smaller installations like home/small shops).

-Bill

Re: XW inverter questions?

Skip,

I am using a 3kW Grid Tied system (3.5kW of STC rated panels for ~4,800 kWhrs generator per year)--so I cannot tell you about using any off grid type system from my experience...

If you are trying to run 3 phase equipment, I don't think you would see any differences between 2% and 5% THD.

I setup a friends machine shop in his 2 car garage with several 1-5 HP pieces of 3 phase equipment (a couple Bridgeport Mills, an old WWII 5hp turret lath, a 1 hp turret lath, and a 5 hp CNC lath). All running off of single phase 240 VAC using a 5 HP idler motor to create fake three phase power. For the CNC I wired the electronics so that they would draw power from the one true 240 VAC single phase--but otherwise the rest of the equipment was unmodified.

I am sure that the 3 phase power generated this way was not very good, but all of his equipment worked just fine (plus the more 3 phase motors I turned on, the more they helped the original idler converter-motor generate the additional phases). We had more problems power droops when he first turned on his equipment (cycling the power on the air compressor would sometimes cause the next door neighbor's TV problems).

We reduced the voltage droop problem by choosing multi-horse power equipment that used clutches to stop rotation instead of of turning motors on and off all the time (or in the air compressor's case, used an unloader instead of an electric pressure switch). Worked very well for many years.

Solar PV works well, but if you are going to use large amounts of power--it is going to be very expensive to install and maintain an off-grid system.

You would probably be better off estimating how much power you will use, figure out how much an off grid system would cost vs finding a place with power nearby--and see if you can use the difference in costs between an off-grid system vs a grid tie system and use the difference to pay for running utility power to your land.

For a full off-grid system, you will need a generator--so it would probably make sense to size the generator to run your shop+home loads (+ charging) as there will be times (especially during the winter) will you will not have enough solar power to run your loads.

And, if your shop loads are highly variable (few days of heavy use, weeks of light/no use), it probably would not make economic sense to build a solar array that could handle 100% of the loads all year round--but use the generator instead for those days when you use the heavy equipment.

If you are talking about under 5 HP manually operated equipment that uses 3 phase power just to power the main drive--You might want to experiment on using a 3 phase converter like I did... Installing 3x 6048 inverters seems to be way expensive overkill for a small installation. You could possibly even avoid a 3 phase generator...

In the end, you are talking about a very large investment in power for your new place--you should probably try mocking something up first and make sure how much it will cost for your place. And make sure that it is economically practical.

Here seems to be a pretty good link that goes into the details of a single to three phase converter and the issues. Mine was a simple design--just a 3,5xx RPM Y wound 5 hp motor and used a small 120 VAC motor with a fan belt looped around the shaft to spin the motor up to near full speed. A rope pull also worked fine, but the starting load from low RPM and to full speed was pretty severe (see neighbor's TV for details).

-Bill

Re: XW inverter questions?

I am not saying--because I don't know...

-Bill