Grid Tie Inverters

Discussion in 'Connecting to the Grid' started by murray2paddles, Aug 1, 2009.

  1. murray2paddles

    murray2paddles WindyNation Engineer

    I have been speaking with Marcel on some issues and have suggested we move those conversations to the forum so everyone can read the responses.
    I will again ask Marcel those questions, ( hope I can remember them ) :oops:

    Marcel. are we able to use an ordinary watt meter to measure the output from an SWEA inverter or do we need a special type of meter ?

    What are my total potential watts using the Windy 750 and 4 SWEA inverters ? Do I need to use 4 for safety or could I just use 3 inverters ?

    I have never seen my units blink up to the advertised 8 green blinks. We just recently had a tremendous storm and the units ran great, but never reached beyond 6 green blinking. Can you explain why my units are not reaching their potential amount of power? Will it have anything to do with the way we now have our chips tuned. ?

    My inverter chips are tuned with start up at 21 - 45 V and the units are running smoothly. but I would like to get more power from them, how do we tune for that and how will it effect the turbine start up wind speed. ?

    The green blinking lights are confusing. On pg. 25 is says each unit can blink green up to 8 and this will show the amount of power being produced. When I put a watt meter on one inverter when it is blinking 5 times I can receive a reading anywhere from 37 watt up to 160 watt and all while it is blinking 5 green. Can you explain why such a difference in watt reading while showing the same amount of green lights ?

    thanks for the ongoing customer support / service

  2. Minnesota

    Minnesota WindyNation Engineer

    Great discussion. Whoever comes up with a clean turn/key 1000w GTI setup for use with the Windtura 500 will get some good business. Based on the recent testing to document the power curve for the "500," I think WN will see a ramp in orders. It is a far superior system to anything in its class, and AMERICAN MADE.

    See my vid:

    Here is a vid by an electrician spinning a 500w and 1000w Windmax turbines on his house, one on SWEA and one on a SUN GTI (China).

    The real need is 1000w UL approved and 12-70V range, for <$300m, and 90%+ efficient.

    Make it so!
  3. bluejay

    bluejay WindyNation Engineer

    motors from china :?:
  4. windyguru

    windyguru WindyNation Expert

    Yes Bluejay, this has been well established by now:

    The blades, hub, yaw mount, tail boom, tail mounting bracket, directional tail, yaw bushing, slip ring, and the stainless steel nuts/bolts/washers are made in the USA. Additionally, the electro-coat and powder coat are done in the USA. The generator head comes from overseas.
  5. bluejay

    bluejay WindyNation Engineer

    I was just correcting him its not %100 YET...My buddys dad has been asking alot about them as he is VP of a local electric motor company.He was very interested in my turbine flying and I told him I would talk with him what kindof of figures it would cost to make them here by US.I will stop in someday this winter..
  6. murray2paddles

    murray2paddles WindyNation Engineer

    Hey Dudes, this thread is supposed to be about grid tie inverters . Maybe you should start a new topic of made in America only.
    Really, now Windy sells globally right ! So for those of us who are international customer many of us probably don,t give a crap where it is made as long as it works well and is affordable.

    :evil: :evil: :evil: :evil: :evil:

  7. windyguru

    windyguru WindyNation Expert

    Yes, grid ties it is! BTW Murray, I finally found the wind meter ... it will be on the way soon.
  8. murray2paddles

    murray2paddles WindyNation Engineer

    The new relay that Mark has worked on has arrived and is wired in place.
    Now if the grid goes out instead of lost power due to the grid tie turbine shutting down, Mark has set up new relays that transfer the power to my battery bank.

    After brief discussion back and forth we came to an understanding on how it would fit my system.

    In the photo you will see blue wires coming in from the Windy 750
    Left set of red going out to the inverter system rectifier. ( SWEA inverter system)
    Lower set of red going to a new rectifier which leads directly to the battery bank.

    The battery bank still runs on the same controller and dump load system due to it responding to V in the bank and not how many turbines are feeding it.

    You will see a light black wire coming out of the lower right side, this goes to the house grid and powers the coil. When the home grid goes out and no more power flowing through the wire the relays redirect the flow of turbine power.
    [attachment=0:2k7vscxr]new relay system.jpg[/attachment:2k7vscxr]

    Josh, do you think I should be using a larger amp Windy rectifier for this and if so please send one. ( thanks )


    Attached Files:

  9. mark99

    mark99 WindyNation Engineer

    Looks really good.Nice install.I think the rectifier was rated at 50 amps . it is marked on the side. What I did not mention is it should be mounted on some metal to wick the heat off that it may generate during high power out put. I know it was rated for the 500 watt turbine.Thanks for getting it up and running and let me know if you have any problems Mark
  10. windyguru

    windyguru WindyNation Expert

    Looks good and a very good idea.

    How many amps does the relay draw? I assume it is in the milliamp range so I guess it is basically consuming nothing.

    And when the grid comes back on, the relay is re-energized and it goes back to feeding the grid?

    The rectifier should be fine if you got some type of metal you can use as a heatsink. But I will just send you an 80 amp rectifier with the wind meter.
  11. murray2paddles

    murray2paddles WindyNation Engineer

    Hi windy,

    yes it is in the milliamp. ( about 125 per )

    The original safety relay that was on this inverter unit had a 10 amp relay and unfortunately it burnt out.
    Mark and I decided to raise the amps and to go well beyond what was probably going to work, so each relay is rated at 40 amp
    The power to activate the relays from the home grid is through a plug in `12 V transformer which is wired into the relay system.
    When the power fails from the home grid this activates the relay and then transfers the power to the battery bank. When the home grid comes back on this again will activate the relays and the turbine power will once again be directed to the grid tie inverter system.

    If any of my information is incorrect I am sure Mark will come on board and make it right.

    I don't have much patience so will probably just pull the land grid plug during the first good wind just to read the amps transferring from the grid tie turbine to the batteries. :roll:

    Josh, thanks for the support you have given us to make it happen and will look forward to the rectifier and wind monitor.

  12. mark99

    mark99 WindyNation Engineer

    The relays total draw was 124 milliamps .That is what my meter read. Murry had all the information right. The relays are powered closed with the grid feed and the windmill is connected to the grid tie in inverter. When the grid shuts down the relay coil is shut off and the contactors switch to the bridge rectifier to connect the windmill to the battery bank. When the grid power returns the relay coil is powered back up and switches back to the grid tie in inverter. As I am sure you know their can be unforeseen events between an idea and the real world. I tried to find a relay that drew as little power as possible and still have a contactor rating to properly handle the amperage generated by your windmills. Time was pressing because his braking relay on his system had failed. Murry was kind enough to be willing to test this for us. I have let him know that he can share any information with you that we share in our e-mails. If this proves to work well I will be happy to share it with everyone. First do no harm! Take Care Mark
  13. windyguru

    windyguru WindyNation Expert

    Hi Mark and Murray,
    Thanks for the posts. I think it is a very creative idea.

    We actually have a product coming out any day now that is similar but serves a different function. We already have them in stock but I have to finish the manual and product listing. I am actually working on it right now :D. They are Low Voltage Disconnects. What they do is very simple:

    You hook them up between your DC load (say 12 volt lights in your shop) and the battery bank. They monitor the voltage of your battery bank and when the voltage of the battery bank drops to an unsafe level (10.5 volts for a 12 volt battery and 21 volts for a 24 volt battery), the relay trips and turns off the load. They turn the load back on at 11 volts (12v system) and 22 volts (24v system)

    It seems that these could be configured to switch on a load when a different load goes down. Or, in other words, turn the battery bank on when the grid goes down. I will ask John who is our electronics guy and designer of the LVD. But, these would definitely need bigger relays. The 12v relay can handle 40A and the 24v relay can handle 20 amps.

    Anyways, I am interested to see how this works for Murray because it would be a nice and simple solution for many people. Good work guys.

    Here is a picture of the Low Voltage Disconnect (or should we rename it the "No Grid Re-Connect" :D ) :

    Attached Files:

  14. murray2paddles

    murray2paddles WindyNation Engineer

    Hi Windy,

    I will be able to report on how it works real soon. like I said earlier I will not wait til the home grid goes out during a power failure, I will create it by just shutting down the power supply to the inverter system and the relay coils. I will then be able to monitor and take amp readings as the turbine transfers power to the battery bank. Wind blew pretty good last night but I am choosing to do this monitoring during day hours so I can be available and fully aware of what is happening .

    Now the part on sharing with others, giving this some thought this is what I have concluded, ( I should have talked to Mark about this first) as the amount of customers increase in the use of a grid tie system and if the product manufactures do not yet have this option built in to their inverter systems and there is a demand for the relay system........ one option is Mark sharing all his knowledge on how to construct your own. Ok that works.
    BUT there is a reason why I am a part of this testing and that is to remind the Marks and Windy's of the world that give us all the info you have and that does not mean we will understand it :roll:

    So unless Mark wants to quit his day job and stay home making these units the next most useful way is for us to stimulate others like you Windy, to build on our ideas and then construct them and make available at a reasonable cost to everyone. Then the electrical challenged persons such as myself can make use of it with no frustrations of trying to understand the coils, amps, relays. etc. :D

    Those who are the enlightened ones can still make their own. :idea:

    Good product you have shared with us on the V battery control. Keep up the good work.

    I do know someone who is going to send me a wind monitor so when they do I will also be able to include more accurate information on wind speed vs the amps reading.. lol

  15. Marcel

    Marcel WindyNation Engineer

    Hi All,

    SWEA stands for: Solar Wind Energy Applications.
    i'll try to let you understand how SWEA inverters are actually working.

    In the beginning when our company started we designed a small 300 watt wind turbine together with a small grid tie inverter who fits for wind and solar.
    Today there are lots of different turbines and solar panels with all different specs...
    the best part of our inverter is that it'll fit on most low voltage turbines or solar panels with a dc voltage from 21 volt up to max 55 volt DC. max 250 watt. max 7,25 Amp.
    Because there are so many different turbines and panels you have to adjust the inverters chip to match with your system. In other words,. to give the right load to your system. This is the key in the world of wind turbines. When you do not do this probably there is to less power or in the worst case to much...
    There's no MPPT sytems in SWEA inverters. ("Guru")
    You can adjust the inverter chip with a special made SWEA RS-232 cable and a computer. Just download the SWEA Inverter Tool (sit.exe) at
    if you like i can send a manual how to install and eventually how to adjust. just mail me
    this is how the tool looks like:
    only use this tool with V2.179U... chips. if you have 071230U6.. chips, they are adjustabel with Hyper Terminal not with the SIT tool. (mail for HT questions)
    also only use this program to adjust the starting voltage and steepness / slope. all the other parameters can be in use for debugging but they are not giving the right info. so please do not ask questions about the SIT tool that isn't giving the right info.... :geek:
    please see the following graph of the SWEA inverter Possibilities:
    [attachment=0:3h6jgslv]graph 20-55 3 points.jpg[/attachment:3h6jgslv]
    off course there are more possibilities. these are just examples. if you are having more inverters you can set them cascading. in this way you'll be efficient in low wind speed. one starts after the other. now you are creating a power curve with more power points.
    The inverter can handle max 250 Watt. so when you want to put 250 watt at 55 volt to the grid you can easily calculate the current. 250 w : 55 v = 4.54 amp.
    SWEA inverters can handle max 7,25 Amp. When the inverter gives full load the green led is blinking 8 times.
    so when you know the starting voltage and the ending voltage you'll know the DC voltage working range. for example v-start 35 volt. V-end 55 volt. (the dump load will switch on at 55 volt.) working range = 20 volt. now we have to know the steepness / slope. this means with how many volts up there's every time 1 Amp more. Just divide the working range by the current and you'll have the steepness. 20 volt : 4.54 Amp = 4,4 V/A. (Max steepness = 4,8 V/A!)
    It's very Imortant to use decent cable for the turbine as well for the grid cable.
    when the tubine calbe is to thin and to long the turbine isn't braking fast enough and causes overvoltages... :cry:
    When the grid cable is to thin and to long you probably have a big impedance on your grid and in this way the inverters can't lose their power trough this cable.
    the next thing what happens is that the grid voltage on the inverter side gets higher than the grid really is.. now the inverter communicates with 4 x red led blinking (grid to high) and shuts down. we can colve this problem by installing a chip with a higher grid voltage range but this will not solve the grid impedance problem. when you have a grid impedance problem you'll know this when having humming tranformers and fluctuating output power.
    you can test your grid impedance by installing a big load (500w light or 1 Kw heater) and see how far the grid drops. (this must be on the same place where the inverters are.) than calculate the current while the load is connected. Watts / volts = current. or just measure.
    than divide the difference between load and without load by the current. this value must be lower than 0,5 Ohm.

    To monitor the output power you can install a simple kw/h meter. please note that not every kw/h meter can monitor power backwards.

    Hope all this info is clear and understandable. there are lots of things that can effect your grid tie system.
    UL aproval is still pending, we have to take care of a lot of UL things :evil: i'll let you know when it's ready. same for the SSD system.

    feel free to contact me, i'm happy to help you out.

    kind regards,

    Marcel van der Heijden
    SWEA Europe / USA
    After sales / warehousing

    Attached Files:

  16. murray2paddles

    murray2paddles WindyNation Engineer

    Great post Marcel., thanks for all the information.

    Well Mark we have blast off. ! Finally a breeze blowing and the turbines are turning pretty good
    The SWEA inverters are running real smooth with the 750 Windy turbine so as promised i will not wait for a power outage.

    So , Murray pushed the home grid power switch that is connected to the new relay to OFF .

    Immediately the inverter system shut down. Usually the turbine would be braked and would not be delivering any power but this time due to Marks relay the coils switched the relays to now deliver the turbine power to my battery bank.

    i then used my AD / DC clamp meter on the live of the wire leading to the batteries just after the rectifier.
    I will post a photo to show the amps that would then be saved during power outage to the home grid.

    Congratulations Mark for making it happen. Hopefully now others will be able to make use of this system and when Josh;s team has the time maybe they will be able to create a packaged unit for their store.

    [attachment=0:3esvil67]marks relay amps.jpg[/attachment:3esvil67]

    Guess I will be shoveling snow tomorrow. :twisted:

    Attached Files:

  17. windyguru

    windyguru WindyNation Expert

    That is great that it works! I usually have to do something 100 times to get it to work properly. Good job guys.

    Maybe Mark wants to build them to order :D ?

    Man, I have to find a good chunk of free time to really read Marcel's post so I can thoroughly grasp what he is saying.
  18. mark99

    mark99 WindyNation Engineer

    Thanks Guys,
    I am really glad it worked well. I have been hoping for some wind to give this thing a test drive. Murry, did you get a chance to measure the AC amps on the 3 wires coming from the windmill? It should be about a third the DC amps on each wire. If it is in the ball park then we should have a sound system.
    Josh, I sent you an E-mail on the relays and how they worked yesterday. I have had plenty of 100 tries before finding a firing solution. The important thing is not stopping at 99. Take Care and Thanks again Mark
  19. mark99

    mark99 WindyNation Engineer

    Murry and I have been working on a transfer switch for his windmill that feeds a grid tie in inverter. What he wanted it to do was transfer the power from the windmill to his battery bank in the event of a power failure. What I was looking for was a 3 pole double throw relay with a 120 volt coil that had a contact rating of 40 or 50 amps. All I could find were expensive and the coil drew more power then I wanted. I ended up going with a single pole double throw relay times three. I had a 300 milliamp 12 volt DC transformer so that’s what I used for coil voltage. I had Murry install it on the 3 AC lines coming in from the windmill. With a 3 phase system the amperage is shared by the three wires evenly. This should not over current the contacts on the relays. I put the windmill power coming in on the common terminal. I put the inverter on the normally open terminals and the 3 ph bridge rectifier on the normally closed terminals. I tied the power feeding the three coils together to make it act as one relay. When the relays are powered by the transformer which is plugged in to a grid powered receptacle the common and the normally open terminals are connected. When the transformer is not powered the common and normally closed terminals are connected. It is my hope that this is something that many people can use. The relays I used are built by NTE Electronics Inc. The relay is #R51-5D40-12F.They have numbers to identifier the terminals. The common terminal is #30.This is the terminal that the windmill wires go to. The 3 wires supplying the inverter go on terminal #87 and the 3 ph bridge rectifier wires that feed the battery bank go on pin87A. The 12 volt dc transformer wires go on terminals 85 and 86. I have sent a copy of the physical properties of the relay in a PDF file, as well as a picture of the 3 relay switch. Murry has been using it for a few weeks now and it is working well. This unit does draw power all the time to work but it is very little. I had a total power draw of 124 milliamps to power the 3 coils of the relays. I am putting this out here for any one that may want to make it and hope the people who build inverters might think about building it into their units as an option. I would be happy to answer any questions I can, Thanks Mark99[attachment=1:33ssbsdn]windmill transfer switch.jpg[/attachment:33ssbsdn][attachment=0:33ssbsdn]R51.pdf[/attachment:33ssbsdn]

    Attached Files:

  20. mark99

    mark99 WindyNation Engineer

    The PDF file did not transfer properly.If you go to NTE Electronics and type in the relay number R51-5D40-12F you can pull up the property file on the relays.Sorry Mark99

Share This Page