Here is my 16' dual rotor. after a stator melt down caused by a nor-easter last fall, everythings been fine. I made 2 more direct replacements for the stator and i hope to run this machine for a while.. i have not had that much time to play lately :-/ I have to spent the rest of this year getting the new shop going. anyway, which brings me to this post. I have been playing around with this idea for a while and now that i have everything built up, it seems to work pretty well. I didnt like the idea of dump loads because i was always striving to keep my batteries at their float voltage and this is alot "easier" on them. It seems they take less abuse this way. I also have a complete pentametric system set up and i have to watch the amp hour totals and the efficiency factors to see if this has less of a negative impact on them, or if it will make any difference at all. I cant say this is the best way to control the turbine, but it makes it so that it only really turns on when it needs to. I have alot of solar (1.5kW) and this supplies the house and charges the batts during the day.
This is a weatherproof steel NEMA box that i have attached to the wind tower out back. It is connected to the house by a 2" underground PVC conduit. This conduit carries three 2AWG welding cables for the turbine power output which runs to the rectifier. Also in this conduit is the multi conductor control cables, one of which, is used for this automation system. You can see the panel mounted LED's that are tied into the limit switches of the actuator so i can get a visual confirmation of the position of the switch. I have these postioned so i can see them from the house.
Im just as guilty as everyone else lol, I think it IS a better idea not to have slip rings lol. Its not very turbulent in my area, so it seems to work out well. Its easier this way. Anyway, this is the plug box that attaches to the back of the NEMA box and protrudes into the inside of the tower. It holds the outlet recepticle that the large 3 pronged plug plugs into. the cover can be secured, preventing anyone from pulling the plug out.
Here is the plug. The excess cord dangles inside the tower legs and when it gets twisted, the plug can be unplugged and unraveled, and plugged back in. Pretty easy, works well. I would have used a twist-lock type plug, but i had trouble finding one which had an equivalent 50A rating. so i used this type, not a big deal.
Here is the view inside of the NEMA box. You can see the type of knife disconnect switch i used. I would have loved to use a 3 pole switch, but i didnt have one laying around. I think this works just as well, you can see, i bridged the 1st phase across the top two fingers. and the other 2 phases to the lower half of each knife. When the actuator engages the switch in the up postition, all 3 phases are effectively shorted out. The things that look like fuses, are not really fuses. they are jumpers. I took them apart and took out the fuse elements. I then used 4awg wire to bridge them, so they effectively became jumpers. It was easier than finding a way to connect the cable dirrectly to the lower fingers.
You can see the control cable and how it breaks out to the terminal strip. eventually the other wires will carry a constant 24vdc, the anemometer signal which is then supplied to a comparator. This will determine, by judging wind speed, if the turbine will come on or not. This will help protect it and will shut it down in a high, sustained wind condition. A little safer. I dont have to stress at night if the wind picks up lol (thats how i blew up the first stator).
The actuator is made by LINAK Corp. It seems to be very well made and i think it was NOS. I had gotten it off of ebay for around $50 if i recall. Although the speed is a little slow for this application, the torque is of no concern because it claims to have 400lb. of lift lol whatever, it works well.
Another shot of inside the tower box.
Here you can see the ALM control module, that i use with my SW PLUS 4024 inverter. I have the voltage thresholds set to turn on RELAY 10 (turbine activation relay) at 24.5vdc and to turn it off at 26.5vdc.
This allows it really, only to run when its needed, because the batt voltage rarely ever goes that low... the solar keeps it up. This relay is also tied into the temp compensation part of the inverter. Relay 8 is the relay that controls the dump load circuit (110vac through the breaker panel). This is still active when i decide if i want to plug in a dump load such as a oil filled radiator heaters in the winter, or air conditioners in the summer. I tend to not use this dump load circuit as much as i used to, and with the automation relay, the turbine simply does not have to come on at all as long as the battery voltage is kept up.
Another neat feature that i incorporated, was the use of RELAY 11 (error relay). Under normal circumstances, this relay is energized. If at any time, there is a problem with the inverter, or it reaches an error state (over voltage, over temp, etc.) the error relay de-energizes. Also, if at any time the control voltage is lost to the secondary relay panel, the turbine control relay drops (blue relay - its wired for reverse logic) and the turbine will shut down. The control signal from Relay 10 is in series with Relay 11 so if there is an error state, the turbine is shut down automatically also. This is more like a safety feature, and i sleep a little easier.
Here is the schematic of the automation system. you can see how it utilizes the ALM to control the turbine and the anemometer to sense wind speed. I want to eventually use some type of programmable micro controller to take the place of the comparator and it would be nice to have manual control of the turbine through the touch screen terminal i use to run the pentametric communication software.
By the way, there is a write up on the pentametric system in the latest issue of Homepower magazine if anyone is interested. :-)
Overall, this seems to be working out good for me. Although I always should keep a close eye on the system as it grows, I seem to be increasingly busy lately and its nice to not have to worry about the turbine smoking another stator, or having to manually shut it down every time there is a storm. Time will tell though. just figured id share it. :-)
Have Fun,
RoyR
KB2UHF