Multiple turbines and GTI's I agree when using multiple turbines they should all be on their own systems. From what i have found with the WM's is the MPPT on the GTI's work best with one turbine however you could run them all into one GTI like a 250w 10-30vdc and then switch them to their seperate higher volatge GTI's inverters. I have experimented both ways on the low end with tieing them altogether. In the lower winds their is not a big loss with MPPT by joining a few turbines together with one inverter under 10 MPH but in the mid to high winds (12MPH and above) there is major loss if you combine all the inverters and all turbines together. So at the least each turbine should have it's own GTI at some point in the mix. (again it all depends on the PMA) High volt rules. The only question now is how long will the bearings last running them at the higher voltages since they have not been tested this way.
I know but with the different winds that I have here. Both turbines produce the same watts on different GTI's on occasion. Most of the time when they disconnect I only see one producing power. I saw the 3 blade doing 400 watts today and the 5 blade doing just 80 watts. This was during a gust but this is happening all the time here. Since I hooked up the disconnect switch.
If I have good enough wind before the trees are full of leaves. Not too long from now. I will post a video of the big mismatches on power here. Today the wind was from the north and the one in the back has a big advantage in that situation.
I found a $16 SSR that can handle 10A of 115Vac to activate/deactivate the 10-30 unit at ~20V. Would the activate time switching the AC be a problem? ... meaning as the voltage dropped back into the teens, and the 10-30V unit turned back on, there is a activate time of perhaps 5 seconds before inverting gets going. FETs could be used on the DC side (rather than a relay) but a good heatsink (and associated losses) would have to be acceptable. I'm not a fan of relays.
Larry, I admit defeat on the subject. I have been playing with the switches at different wind up to 15 mph. As long as both are getting wind and making power. No matter which turbine I turn off I see at least a 50% drop in power. So even if it is gusty you would not loose that much til one caught up with the other turbine.
Do you think another blade adjustment is needed for the (5) blade turbine? Maybe the 3 blade is now making more rpm's then the 5? Just a thought.
The boards will be in after April 22. I have been doing simulation with all info I could find. So far this setup is the best I can do till the parts finish arriving. All ammeters are within ranges that will allow the circuit to run all the time. TL082 operating range on output is 40-60 ma so I am good. Relay draws 160 ma so I should be good. LED Max is 30 ma so I should be good.
Well sorry to inform everyone the Tl082 will not work for this switch setup. Relay stays energized when GTI power is not applied. So it triggers like this ON 0-8 volts OFF 9-14 volts. That is what I set it at. ON 15-60 volts Went out and bought a LM339 Comparator. Wired it in. Found out the hard way it needs power to the output to work. So far so good it is working and testing is commencing.
$16 10A SSR: http://www.mouser.com/ProductDetail...=sGAEpiMZZMtq49AUx5G37x4sUP8FBQ5O5nWu5w7eSY8= N.O., so it would have to be driven ON to activate the 10-30V GTI then driven OFF at ~19V to let the 22-60V take over.
I checked and when incoming voltage from the GTI drops below 8 volts the relay came on. Above 8 volts it is off and then when it gets to 14 volts which was the set point it switches back on. That is why I changed to the LM339 Comparator. Now it works fine with any voltage from GTI. Also did not go with SSR as all I could find is NO when I want NC contacts. This circuit I just checked uses less that 10 ma when not engaging the relay when it does it only goes up to 150 ma. Also the relay is good for like 150,000 contacts which for me would be like 5 years. Also if it goes bad it will not hurt anything.
OK, I guess when you say "the GTI drops below 8V" you really meant the turbine. The SSR could be used just flip the + and - on the LM339. What circuit sim program are you using?
Yes on the turbine voltage part. I am using circuit lab online but it does not have the LM339 in it. So I am just doing all modifications at home and putting into Eagle Cad to make the circuit board. I spent way too many hours on this Eagle Cad program but I have figured it out.
OK to please everyone. The board has been done on the PCB maker both ways. Had to move a bit around to keep it one sided PC board but it is done. There was a wire running between those lines I had to switch. Added a little to board length to make it happen but done. Green LED power indicator for 12 volts input and Red LED for relay energizing added also. Also silk screen will show which board it is Mechanical or SSD relay needed.
You gonna etch your own board? Aren't you using EaglePCB for the layout? Until you do these a few times you don't realize how much precision goes into Engineering even a simple board. Every part must be an exact fit. Breadboarding is key - get it fully working and then move to the PCB step. It gets even more involved if you are designing for production. I'll be proud to see your board when you get it done Tom. Video of a similar process I went through last year on my solar tracker prototype:
The boards I am going to have them manufactured. http://oshpark.com/ I am using EaglePCB Version 5.11 for the prototype. I have been printing it out to check components for fit. And yes it is a learning curve. I first made it and then checked after printing and found out had to change the resistors to a longer length as well as the fuse holder was the wrong type. Even though it was right by the description. Not quite done but close. I am still waiting on the adjustable 10K resistors. The ones I wanted to use I could not find. So I changed the PCB for the new inline ones I have ordered. I will check them out when they arrive next week.
