Hybrid system ???

[mgtd]

I currently have a 10" Otherpower scratch built mill and 860 watts of solar feeding my 840 AH, 48V  battery bank which feed an Outback 3048 inverter.  I'm powering about half of my home/shop 120 volt requirements. (haven't addressed getting my 240 volt requirements yet.

Available to me, is an Enertech 1800 mill (Used and needing a little work)  This unit supposedly produces 1.8KW of 120volt AC (in 24 MPH wind)and requires AC input voltage (for coil excitation)--thus it is a Grid Tie unit, and as a stand alone, would not be able to produce any power if a power company outage occurred.  

My thoughts are to power the Enertech from my Outback inverter and use the Enertech output to power some critical circuits (fridge-freezer) and maybe a trickle charger for my battery pack.

I'm new to this, so don't flame me too bad !!  I'm looking for downsides and constructive criticisms of my thought process and feasibility of this integrated concept.

The Enertech 188 has a noisy bearing in the gearbox and should be a relatively easy fix.

[TomW]

mgtd;

It sure seems I read here once about someone using the output of a pure signwave inverter to trick a grid tie inverter to produce into that setup. Sure seems like a decent sinewave inverter feeding loads qualifies as a "grid" although a small one.

Just recall reading that I have never tried this so take it with a grain of salt as they say.

If I were to try this I would isolate the inverter AC out with a 1:1 transformer and use proper fusing, however.

Good luck with it.

Tom

Tom

[Flux]

I suspect the Enertech uses an induction generator for grid tie. You could presumably supply the magnetising current from your inverter but I don't think the inverter will be happy to be back fed from the induction generator. These induction machines need to be tied to a grid of greater capability than themselves and I think you are heading for disaster with no control over loading.

If the Enertech is something else then much more information is needed, ac excitiation is only likely to be possible on an induction machine. If it is an induction machine then you could self excite it with capacitors but you would need something comparable to a hydro load controller to regulate it and I doubt that it would be practical with the changing loading of wind power. You may be able to self excite it and transform down and rectify to charge the battery but I doubt that you would get much of its original rating. I think you are on a looser for anything than its original grid tie application.

Flux

[DamonHD]

The SMA Sunny Island and Sunny Backup systems, and similar systems from Outback and Xantrex I believe, are happy to create a local grid that other grid-tie microgen can sync to and push energy into (to go into batteries or a dump load).

That's what I want to do with my house on my next round of PV if I can.

Rgds

Damon

[mgtd]

Yes, it is an induction generator.

[electronbaby]

I have to agree with Flux. The Enertech is an induction machine, and as he stated, you would be foolish in trying to connect it to anything but the grid. In my opinion, it would need a load greater than what you are supplying it for it to work properly. Im sure it could be done with some careful programming and hysteresis control, but Im not so sure it would be what you are looking for.

The Enertech machines were famous for having some mechanical problems, and you might spend more time modifying it to do what you want to do, and or fixing it to keep it running.

Even if you were to make it work, there would be constant losses in the rectifiers, inverters and such that would lose you some efficiency, that could have been had in the first place had you gone with a machine designed to do what you want from the start.

If the Enertech is free, or very cheap, it might be to your advantage to snag it and play a little, but if its close to a substantial investment, I would look else where.

[dnix71]

This place had one for sale used. There was a control box that went with it. Overspeed protection was an internal brake, but the control box had a windspeed meter. It looks like it was only safe with a proper grid tie.

http://www.kansaswindpower.net/used_wind_generators.htm

This man went off grid but couldn't use Enertec mills off grid, either.

http://209.85.165.104/search?q=cache:51nZcZvnS3IJ:www.faracresfarm.com/jbvb/ae_house.html+Enertech+1
800+off+grid&hl=en&ct=clnk&cd=8&gl=us&client=firefox-a

[richhagen]

I suspect that when you backfeed that power to the inverter, the voltage and/or frequency are going to get out of whack quickly and the inverter will detect it as a fault.  I have never tried anything like that.  I have heard of people using induction motor based generators for battery charging, and you might be able to rig the turbine to do the same.  I do not think I would try backfeeding that much energy into your microgrid - it is over half of the full power rating of your inverter, I would likely try to make it stand alone and rectify it to charge batteries.  It might not be the most efficient, but if the price is right then it may be worthwhile.  Best of luck with it.  Rich

see:  http://www.linux-host.org/energy/einductge.html  

[ADMIN]

Also be aware that there is a very good reason that so few old Enertech machines are even in operation anymore. The gearbox was extremely complex, and very expensive to rebuild. Maybe it's just a main bearing problem, but are you SURE? Have you had an Enertech expert, like the folks at Lake Michigan Wind and Sun, look at it? Have you contacted Enertech? They sell refurbished turbines, and also sell a smaller and brand new design 5kw turbine.

If there's a serious problem in the gearbox, it will likely be more cost effective for you to simply buy a Bergey Excel or Proven 6600 or ARE 442, or build your own 17 or 20 foot machine. With a VERY sturdy tower to match. Or, get a new

As for providing your own "grid" with an Outback inverter -- Enertech machines were grid synchronous. Even their new E6 5kw machine is grid synch, no inverter (pretty cool!). But are you sure that your Outback is capable of performing 'stiff' enough for a grid synch turbine of that size? Have you contacted Outback to ask? Outback will be the 'horse's mouth' on your question, and either Enertech itself or Lake Michigan Wind and Sun will be able to tell you exactly what you have -- and what you don't.

ADMIN