Will a Classic/Clipper Combo work with this wind generator?

[tuckersnocat]

Hi All,

I'm new to this forum and am hoping that you can give me some advice about adding a wind turbine to my small off-grid cabin system. It's high in the mtns of SW Colorado.

I've got an opportunity to buy a good used 3.2 kW wind generator (Proven). It will produce 3 phase AC variable voltage power (200-225 Vac 3 ph). Nothing else would come with it so I'd have to purchase all of the other components needed to use the power. I was directed here from another forum and have looked at the Classic/Clipper info. Would the Classic 250 with a 4000W AC clipper work for my needs or would something else be better?

The rest of my system consists of:
-24V lead/acid battery bank
-720W of PV through an Outback MX60 charge controller.
-24V microhydro generator which is used with a Morningstar load diverting charge controller in the summer.
-SW Windpower 24V 300W wind turbine which we really just put up to get a sense of how much wind we have - the answer is not a tremendous amount but it's nicely complementary to the PV. It's usually either sunny or windy at 11,000 feet in the mountains.
-Outback 2500W FX Inverter w Mate
-Outback AC and DC Enclosures
-Generator, several for different puposes but mostly a Honda EU3000is at present.

I would appreciate any advice!
Russell Hill
La Plata, NM

[dgd]

I've got an opportunity to buy a good used 3.2 kW wind generator (Proven). It will produce 3 phase AC variable voltage power (200-225 Vac 3 ph). Nothing else would come with it so I'd have to purchase all of the other components needed to use the power.

Is this not the Proven P35-2 model that put the company out of business? - with the discovery of a manufacturing fault leading to broken shaft and the real possibility of blades flying off?  Does 'good used' mean its been re-manufactured?

dgd

[Halfcrazy]

Was it that one or the bigger one? I forget but if it is the one it had a major flaw. In any event I would go with a Classic 200 and Clipper if you have to stay 24 volt on the battery as the turbine will overpower a single classic so the 200 would be a good compromise between headroom and voltage

Ryan

[tuckersnocat]

Thanks for the input guys. No, this isn't the one that had the shaft problems, this is smaller than that model and has a good record for reliability. This particular unit wasn't ever commisioned, it was a dealer display model but it was set up on a pole outside for a while.  Buying used is always a gamble of course but this one sounds like a good bet.

I would like to stay on 24V as so many other parts of the system are set up that way. Ryan you said that the turbine would overpower a single classic, but are you saying that a single Classic 200 and Clipper would be OK? Is the 4000W AC clipper the right model to use?  How about the resistance value, any suggestions there?

Thanks Again,
Russell

[boB]

It will produce 3 phase AC variable voltage power (200-225 Vac 3 ph).

What I am concerned about is that 200 to 225 VAC.  What is the wind speed at those voltages ?

It may very well be that the DC voltage will be too high for even a Classic 250.  It is definitely
going to be higher than 200 to 225 V DC.

I think these turbines are used more with grid tie inverters like the Aurora or Windy Boy.

I would like to see an MPPT power curve for one of those GT inverters  and this particular
turbine.

boB

[tuckersnocat]

The 200-225 vac is listed as typical during operation. The other typical values listed are:

150-300 rpm
5-25 mph approx wind speed
200-225 Vac 3-ph (Vop AC) Output voltage Vac under normal operating conditions
400-450 Vac 3-ph (Voc AC) Output voltage Vac if grid fault (inverters disconnected from grid)
240-300V DC (Vop DC) Input DC Voltage to grid connect inverter under normal op conditions
400-500V DC (Voc DC) Input DC voltage to grid connect inverter if grid fault (inverters disconnected from grid)

This all seems to assume using a control box listed as ECM2504ME/300 (which contains a 3 phase rectifier) and a Windy Boy grid connect inverter.

There's also a list of maximum values but it's just the upper numbers of each of these categories with the note that the blades feather at wind speeds above 25 mph so the maximum shaft rpm is 300 at any wind speed higher than 25 mph.

Even though this site is at 11,000 feet in the mtns it generally isn't that windy. The max speed ever recorded on our weather station is 49 mph and that was very unusual, our monthly max is usually about 20 mph.

You're right boB that these are usually used with a grid tie inverter like the Windy Boy 5000US, I'm just trying to come up with a simpler, cheaper alternative since I'm going to be using it solely to charge my battery bank. I certainly hope that the grid is going to stay far far away from this beautiful spot.

These are big voltage numbers  but doesn't the Clipper limit the DC voltage that leaves it heading for the charge controller? That was my sense reading the literature, that the Clipper would rectify to DC  and limit the exiting DC power so that it could be safely handled by the Classic. Is there a limit to what incoming AC voltage the Clipper can handle that I might exceed with this setup?

I appreciate all of your input, I did go ahead and purchase the turbine so I'm at the "design the system for it" stage now. I'm planning to be using the turbine for a long, long time so I'll do whatever I need to do to set it up correctly.
I'd like to find the simplest, most efficient and most reliable way to do that - maybe not all possible at the same time

This is a very remote location and there are times when we simply cannot get there for several weeks at a time in the winter due to avalanche conditions and the sheer amount of snow. It's typically an 8 mile trip on skis or snow machines from December through May. It does have internet access via satellite though as long as we have enough power to keep the system up. One of the other items on my to do list is to get the generator autostart set up .....

Russell

[ChrisOlson]

In my opinion the Proven runs at too high of voltage to be used with a Classic.  At your altitude it will have a pretty significant derate factor due to air density so it probably wouldn't over power a single Classic.  But the turbine has to run at the right tip speed ratio to even have a remote chance of making significant power.  And running at the correct TSR its voltage is way too high.

Anything can be made to work - you can use a step down transformer, rectify the lower voltage AC to DC and feed it into a Classic, then use the clipper to keep it below 150 (I think you'll need the 90+ amps output of the Classic 150 for it to work on a 24V system).  But the question of whether or not that's practical comes into play.

I think a better option would be to build a mini-grid with it using AC coupled GT inverters, or use it to direct drive resistive heating.  Both methods would be pretty efficient.  With the first you use your battery-based inverter's output to act as the "grid", and use a GT inverter (like an Aurora) on the turbine output that will AC couple with your "grid" and offset usage from your battery bank by supplying power direct to your AC loads.  With the second method you just have to figure out the resistance of a heating array that will let the turbine run at the correct tip speed.
--
Chris

[tuckersnocat]

Thanks for your input on both forums Chris.

You're right the air is very thin at 11,000 ft but our experience having the little SWWP turbine up for 3 years does show that there's energy there that we can use.

My ultimate goal with this system is the ability to generate enough AC power to keep the satellite internet and camera system on though the winter without having to run the generator. That lets me see and monitor what's going on up there when I can't get there (and I can have it on my screen at work and pretend that I'm there instead). That system doesn't require much power, about 150 watts, but it needs it all the time.

So I need AC power, not heat, and not a whole lot of it but there needs to be consistent low-level input even if it's stormy for several days.  Between the PV and the Proven I think I'll have it covered. If not I'll keep adding more power sources until I do. My priorities are reliability, efficiency and cost in that order.

So with the mini-grid approach my battery bank and Outback inverter would supply AC power to my mini-grid when it's not windy which is most of the time (that's really what I'm doing now I just leave the equipment off in the winter because I don't want to discharge the batteries to the point that they might freeze). When it's windy the Proven would produce AC power through it's GT inverter and would take over the job of powering the grid and charge the batteries with the excess power via an AC charger (the Outback inverter or a seperate unit). I'd also have to deal with any extra AC power that couldn't absorbed by this system.

That sounds simple enough if I've got it right. It sounds like the main question is whether it is more reliable and efficient for the Proven to charge the batteries with an AC charger or a DC charge controller given the power manipulations necessary for each approach.  The secondary question is how much each system would cost.

Am I wrong about what the Clipper does? It's instruction manual looks like it says that it would take the unaltered 3 phase AC from the Proven, rectify it to DC and send it to the Classic in a voltage that the Classic can safely use to charge the batteries. Is that an inefficient process?

[ChrisOlson]

Am I wrong about what the Clipper does? It's instruction manual looks like it says that it would take the unaltered 3 phase AC from the Proven, rectify it to DC and send it to the Classic in a voltage that the Classic can safely use to charge the batteries. Is that an inefficient process?

Does the clipper include a rectifier in it?  It might, I don't know.  At any rate, rectifying high voltage AC to DC is not really that inefficient.  The only loss is the 1.4V forward drop in the rectifiers (diodes).

The main problem is the normal operating voltage of the Proven turbine.  That would have to be stepped down to around 120VAC per leg.  At 120VAC RMS, rectified, you get around 170VDC.  Three-phase transformers are not easy to find - especially one with the right primary and secondary windings in it to step the voltage down to the correct level for the Classic 150.

It was mentioned earlier to use a Classic 200 or 250.  And that would minimize the step down requirement.  But I don't think those put out enough amps on a 24V system without using dual controllers.  With a Classic 250, for instance, your open voltage would probably be in the 270V range someplace (270 - 250) / stator resistance of 1.5 ohm (guess) = 13 amps @ 250 volts = 3,250 watts.  But 3,250 watts on a 24V system @ 30 volts is 108 amps, which a single Classic 250 can't handle.

The thing is, in the thin air at altitude your tip speed ratio (and therefore output voltage) does not change from sea level.  What changes is rotor efficiency due to less dense air, meaning there is less energy in a 30 mph wind at 10,000 ft than there is at sea level (I could calculate it for you, but you get the idea).  My rough guess is that your 3,200 watt turbine @ 25 mph at sea level is going to be a ~2,000 watt turbine @ 10,000 ft at the same wind speed.  So it's still possible, due the derate factor of altitude, that a single Classic 250 might work with a good clipper in case it goes over the Classic's amp output limit.

I cannot sit here and say "do it".  If it was me I'd "Just Do It", but I've been known to blow a lot of stuff up too, when it comes to wind turbines   
--
Chris

[tuckersnocat]

I'm tempted to go ahead and try it myself. The controller seems to be the most likely victim if something goes wrong and that's not too huge a tragedy. I wouldn't want to destroy the Proven though - that would hurt. I think that you're right that the turbine won't produce as much power at that altitude and my wind speeds generally aren't that high. Problem is every once in a while they might be and how long would it take to fry some components, probably not that long.

I've got some time to work this out though, I won't be able to drive to this site until June at the earliest

I'm hoping one of the Midnite guys will chime in with a little more information. Ryan already suggested the clipper/classic 200, any other thoughts guys?
Will the Proven's high voltage damage the Clipper in any way? Will the Clipper be able to deliver power to the Classic at a safe voltage for it? Are there any other "safeguard" components that should be built into this circuit?

Thanks again to all,
Russell

[boB]

The clipper does include a 3 phase rectifier and brake switch as well as the load resistors.

The rectifier isn't inefficient but when you have to load down the turbine because it want to
go too high in voltage, then you would be wasting energy as heat.

I'm afraid that the Proven is more than likely going to be clipping at higher wind speeds.

Also, one Classic working into a 24V battery bank can only put out 1/2 the power it could
put out into a 48 volt bank (approximately)

boB

[dgd]

I'm tempted to go ahead and try it myself. ...
Will the Proven's high voltage damage the Clipper in any way? Will the Clipper be able to deliver power to the Classic at a safe voltage for it? Are there any other "safeguard" components that should be built into this circuit?

The Clipper is not a DC to DC converter. It will simply attempt to dump power from the Proven thereby reducing the voltage to a safe level. This may  actually never be achieved  (ie reduce the voltage) and all that happens is  the dump resistors heat up and burn followed by the Classic smoking etc...  IMHO.. (maybe battery shorting, BIG fire.. )

I looked at this same problem as there was/is a Proven 6Kw and a 3Kw 2 to 3 year used turbines for sale near me. Not such great condition though as both made noise and the service tech reckons bearing problems, needing tightening or replacing. An there is, of course the difficulty of getting spares.
What finally made me go elsewhere is this high voltage issue. I could not find any reasonable cost solution as I too wanted to charge a 24V (1050Ah) battery bank.
Good luck with yours..

dgd

[Halfcrazy]

Well I am in Chris Olsen's camp I would try it but then I am pretty well known for letting the smoke out of things. I am guessing the power is not going to be a huge issue so I would go with a Classic 250 and a Clipper. The only real concern is that IF we get the resistor value wrong on the clipper it can break the classic. But if everything is designed right the Classic should try to Stall the Proven at higher winds and worst case it makes some heat in the clipper but that's what it is designed for.

So I guess in short what I am trying to say is unless something is wrong on the MidNite end the hardware should work just fine with the turbine although it may cause the turbine to not be as efficient as it could be do to holding the voltage down.

Ryan

[tuckersnocat]

Ordered the 4000W AC Clipper w 1.6 ohms for the resistors and the Classic 250 today. I'll post an update when I get everything up and running but that won't be until July or August when the road is open. Thanks again for everyone's input!

Russell

[Halfcrazy]

Russell
I took a pretty good guess on resistor values but we may need to tweak them. Basically when you get it going lets watch it real close and see if the resistance I picked is strong enough to stop it.

Ryan