Classic Current Handling Capacity

[Halfcrazy]

Thanks for the picture Ryan.  Now I can see what you meant when you replied to my other Classic Cooling post.  Loooks like the 8 MOSFETs heat sink on the die cast aluminum case along the right side.  There are ribs on the outside of the case and the "turbo" fan blow across those ribs/fins.  

Was that a Classic 150, 200, or 250?

That 17' turbine put out 9kW peak, didn't it? 

That's a LOT of power to run through one Classic!

- Edward

This was the second Alpha unit to ever go out of MidNite it was a 150 volt unit that I had routinely fed to much voltage. It was tough as a bag of nails the issue was it hit the current limit of 99 amps and the voltage spiked to around 375vdc Over voltage issues are pretty dramatic there will be no hiding the fact the Classic was over voltaged. This is exactly why the clipper is needed.

[keyturbocars]

Makes sense Ryan.  I agree that a higher surge rating in wind mode would be a good idea.  I've seen my HY-2000 turbine putting out 45 amps fairly steady and then for maybe 1 second surge to 65A in a strong wind gust.  The analog ammeter sweeps up to 65A and as soon as it gets there, it starts to drop back down to 40's.  Very intermittent and not sustained. 

[boB]

That is a tough one to explain fully. the higher voltage units do handle less current for a couple reasons as you stated. The true issue is the current limit setting from the factory obviously if we made the 250 say adjustable up to 90 amps people would hook up 90 amps of solar panels and cook it. Now the tricky part wind is usually not steady so say you where running a steady 35-40 amps but a quick gust hits it and it would like to spike to say 80 amps for a second or 2. I think we need to have some sort of surge capability above max amperage setting but only in wind mode? I have chatted with boB about this and it may be something he works out at some point. The Classic would run until it sensed it was getting warm than back its current limit down a touch. Like I said it is a slippery slope.

You won't be able to adjust the current limit on a Classic 250 to 90 Amps...

As far as surge for wind, this is something that, if implemented, will be able to be turned off (disabled).
That is so if one is using the current limit because they are using a smaller breaker size, it will be able
to trip.  The amount of surge will be limited too, of course, but will also be dependent on temperatures.

boB

[ibeweagle]

nice burn out looks like my turbine when I put a 12 foot dim blade on a 10 foot turbine gen turned out to be a 2in hand #18 wire burner rat nester haha tail was tangled up too HAHA DID NOT LOSE ANY MAGNETS THOUGH METAL MAGNET HOLDER WORKED CHEERS Mike maybe have to get a different topice for burn outs? enjoy

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[keyturbocars]

This was the second Alpha unit to ever go out of MidNite it was a 150 volt unit that I had routinely fed to much voltage. It was tough as a bag of nails the issue was it hit the current limit of 99 amps and the voltage spiked to around 375vdc Over voltage issues are pretty dramatic there will be no hiding the fact the Classic was over voltaged. This is exactly why the clipper is needed.

Ryan, So if you had your homemade Clipper (voltage clamp) attached to that Classic, do you think it'd still be alive today? 

[keyturbocars]

You won't be able to adjust the current limit on a Classic 250 to 90 Amps...

As far as surge for wind, this is something that, if implemented, will be able to be turned off (disabled).
That is so if one is using the current limit because they are using a smaller breaker size, it will be able
to trip.  The amount of surge will be limited too, of course, but will also be dependent on temperatures.

boB

boB, I was studying the power curves of the different Classics.  In the current production run of Classics, are these the current limits programmed in the firmware of the Classic?

Classic 150 = 83A @ 48V
Classic 200 = 65A @ 48V
Classic 250 = 55A @ 48V

If not, then what are the current limits programmed for 48V?

I confess that I am itching to try a Classic out, but I realize that I might need to step back and let the beta testers pave the way a little further before I can move forward.

Thanks,

Edward

[Robin]

Surge power is something that we have been experimenting with. We need more units in the field before we can determine just how much surge to allow. To answer your question regarding higher current at lower voltages: the answer is yes and no!. Yes, you definately get more power as the MPPT voltage is lowered. Take a look at the power graphs on our home page. You will see that the output power ratings of the Classic 250 were already based on 180 and 200 volts MPPT. You do not run a 250V unit at 250 volts. This is because of VOC vs. MPP of a solar panel. Maximum power is typically 75 to 80% of VOC. The 250 volt limit is to allow for VOC, but is not intended to run continuously at that voltage. May I suggest you find out what your free wheel voltage is going to be in high wind?

[keyturbocars]

Robin,

The freewheeling voltage on this HY-2000 turbine is something that I would really like to determine (safely).  The controller that comes with the HY-2000 is fairly simple, but to it's credit it does have a safety feature built in.  It has a set of relays that are energized during normal operation and allow the turbine to run normally.  If the connection to the battery is somehow disconnected (which would result in a freewheeling condition), then the relays de-energize and the turbine brake is automatically applied.  Smart idea.

I know I could bypass the HY-2000 controller altogether and set up a rectifier directly to the battery bank with a breaker.  Then I could wait until the wind is roaring and disconnect the battery and measure peak freewheeling voltage.  After my first wind turbine failed (different brand), I am very hesitant to try this.  The other turbine failed when I went to shut it down in 30mph winds.  Having that other wind turbine ROARING for 1 hour as it freewheeled with a burned out stator was something that I never care to repeat!  Perhaps this HY-2000 would never do this, but I am very hesitant.  It's a gamble that could cost me a LOT if I am wrong and also do damage to my home.  My concern would be that at freewheeling RPM, the voltage will be high and then abruptly reconnecting the output to the battery (or trying to abruptly brake the turbine) could result in a spike that might burn out stator windings.  Then I have another runaway turbine that is ruined.  Maybe not. 

Does anyone have any suggestions for the best way to determine max voltage of a turbine?

I suspect that it's just by letting it rip in a freewheeling state and see what happens.  I confess that I'm a bit of chicken in this regard.  My wind turbine is close enough to my house that a thrown blade could be trouble.  On the last turbine, I had my wife and 7 kids hunkered down in the basement while I was running about the farm dealing with other problems during that wind storm.  There was nothing I could do about the runaway turbine.  Like I said, I don't want to repeat that scenario again. 

I've asked the HY Energy factory the question about max voltage, but they did not seem to understand this.  They replied back "about 60 volts" which is the max battery voltage that the HY-2000 controller allows.   Again, to their credit, they have supplied me with detailed data that I think many other wind turbines companies could not even supply the consumer.  I could try to ask them again and see if I can explain it better.  There is a bit of a language barrier, but the person I've been dealing with has been very helpful and quite good with their English. 

All that to say, if someone knows of a safer way to determine max voltage, then I'd appreciate the suggestion!

Edward
 

[niel]

try asking them what the maximum unregulated voltage output of the turbine is so you don't have to disconnect the controller and let it freespin without the load of the batteries on it to find out yourself.

[keyturbocars]

I just wrote another message to my contact at the HY Energy factory, and I am hoping that this time I did a better job of describing what I want to know.  They have done extensive testing and they have the data to back it up, and I am hoping that they will be able to tell me the open circuit voltage (Voc) of the HY-2000 turbine in high winds.

Edward

[keyturbocars]

I checked my e-mail this morning and I received another reply from HY Energy.  The provided me with exactly the data that I requested.  Time and time again, I've been impressed with how professional they have been.  They are a gem among some of the less honorable companies cranking out wind turbines in China and elsewhere.  I am glad that I have a HY-2000 wind turbine.  They have rated it very conservatively (a "2kW" peaks at nearly 3.5kW).  Quality (fit and finish) on turbine itself was outstanding.  It was reasonably priced.  They have done extensive research and then testing before releasing the HY-2000.  Impressive!  

I was very excited to see the data...  OK, I'm a bit of a nerdy mechanical engineering type!  It looks like a Classic 150 will be a great match for this turbine.  As long as there would be some room for surges, I think the Classic 150 would be great even under the highest winds & power output of the HY-2000.  In the past, I asked them what is the safest maximum RPM for the HY-2000.  They told me 800 RPM.  That corresponds to 134vdc.  I would set the voltage clamp (similar to Ryan's except with a Crydom SSR) to max of around 125Vdc to keep turbine RPM's safe and also keep the Classic 150 safe.  By the way, rated power output of 2000w occurs at 534 RPM where it puts out 42A @ 48V according to some other data HY Energy provided me.



Midnite guys, let me know if I am interpreting this data correctly in regards to the Classic 150.

Edward