Hey everyone!
I'm back to this great forum to look for some insight into our latest issue in off-grid energy generation. For a bit of background we are using Classics and Clippers at our remote telecom sites to power our equipment. The solar has been working great, although we don't have much sun this time of year. The wind systems haven't been going so well. The turbine is a HYEnergy HY-1500 tied to a 4KW AC Clipper at 1.6 ohms per phase, controlled by a Classic 250. The battery bank is 530 Ah @ 48v.
About a month ago we discovered that our new HY-1500 wind turbine wasn't producing any power. After a few discussions with Ryan and boB we came to the conclusion that the turbine was the problem, and not the classic/clipper. We removed the turbine from the tower and replaced it with another new one. Things were going great until a few days ago when we visited the site and realized the same problem had appeared again.
Thinking it was simply a faulty turbine, we didn't take the time to determine the true problem the first time (big mistake). After the second unit showed the same symptoms, we disassembled the first toasted turbine to find the slip ring badly burned.
Here's what we found:
(http://farm3.staticflickr.com/2885/11488059564_8403ec0d2e.jpg)
(http://farm8.staticflickr.com/7344/11488077034_a23b37d1f2.jpg)
As you can see, two of the phases shorted together and burned the plastic, as well as pitting the shaft and depositing carbon on the copper. While i'm not a fan of the plastic separator between the brushes, it would seem that a substantial amount of current was dissipated on the slip ring.
Now, for the million dollar question: what could possibly cause this to happen?
Our current theory is that there isn't enough load on the system and the classic is telling the clipper to stop the turbine quite often in very high winds due to the battery bank being in float. This constant start-stop of the turbine in high winds is creating some sort of arcing on the slip ring causing it to burn and eventually completely short. To compound the issue, we (and boB) believe the resistance, 1.6 Ohms per phase, is too low. When the classic tells the clipper to slow/stop the turbine there is a huge amount of current going through the slip ring.
Does this sound plausible? Or am I completely out in left field?
Does anyone have a HY-1500 or HY-2000 operating on a clipper, and if so, what resistance per phase are you using?
When the turbine was operating normally we have seen over 2500 watts being pushed through the classic. Winds at this site regularly hit over 100 Km/h or 60Mph and can gust to nearly 180 Km/h multiple times per year, especially now. During normal operation we have never had any heat coming from the clipper and have never seen the fan turn on.
Anyone have any ideas or comments? We're open to any suggestions!
Thanks
Devo, I didn't know you were this person ! This is great that you have brought this to the forum.
There are lots of good heads on here !
So, we ~think~ that part of the problem may be that the clipper is engaging when there is a LOT of
inertial stored up in that HY1500 turbine and sending too much current through the slip-rings.
I know you have VERY high winds up on that mountain. (120+ MPH I think you said)...
So, you have a 4kW AC Clipper and it is a 1.6 Ohm, meaning that there are 6 resistors, 2 in series
and each one is 0.8 Ohms. I was going to say to place them in series to increase the resistance
but can't just do that because they're in series already.
SO, you COULD just remove one wire of each 1.6 Ohm resistor and then add another power resistor
in series with each one of those to reduce the current. You of course have to be careful not to go TOO
high or else it won't clip... BUT, you can certainly experiment slowly by gradually adding some resistance.
Question is, do you have anything you could try ?
Another idea is to reduce the fail-safe clipping voltage in the clipper to a much lower
value so then there isn't so much power available when it does clip. RPMs of the Clipper will
be much lower too. If the wind power curve you are using is the same as the HY2000 curve,
then the highest voltage is 120V DC. So try bringing the absolute highest clipper voltage down
to around, say, 140 volts or so (a bit of headroom).
Another idea, which we talked briefly about was to add some battery side diversion. You could
do this with Aux 1 and keep the Aux 2 for the main Clipper drive signal.
The best mode for this Aux 1 might be the Waste-Not mode. This will, instead of the Classic
raising its input voltage (turbine RPM and voltage) in Absorb or Float to regulate the voltage,
keep the battery voltage down using the external diversion load. When doing this, you set
the Waste-Not relative voltage at minus 1 or 2 volts. Then, raise the Absorb and Float set-
point voltages a volt or so. When the battery side diversion doesn't work, the Classic will
then raise its input voltage (the turbine voltage) to reduce the battery voltage and then
the Clipper will come into play. That's the fail-safe.
So there are more than one way of skinning this cat but you will still need more power
resistors, either for the Clipper or for the battery side diversion load.
More comments welcome and still thinking about this.
There is also another user here that has a HY2000 and AC clipper (Turbokeys) but I highly
doubt he has nearly as much wind as you have.
How about these guys here ??? http://www.wimp.com/antarcticaweather/
boB
When the battery bank is at Float then why bother with the wind turbine? You obviously don't need the current from it.
Turn off the turbine using a Contactor enabled by AUX1 Float High to short out the three phases. Better in shutdown mode rather than trying to use the Clipper to keep the turbine loaded, especially in those high wind conditions you have. ( just IMHO :))
dgd
boB & dgd - Thanks for the replies! boB you actually spoke with John, I'm Devin, one of the other business partners. John has the electronics background and helps with these sorts of issues. I mainly deal with the tower and site construction aspects. When you spoke with him we were in the midst of the office Christmas party!
I think issues like this can certainly help build the community knowledge base and perhaps someone else who may be experiencing a similar problem. Wind turbines are great when the work, but are very difficult to get right.
We do have a couple of other 4Kw clippers at the office, perhaps we can use the resistors from one of those to test out the theory. It might not look pretty, but it would tell us if additional resistance would soften the slowing of the turbine. Before the last failure, when the clipper would engage the turbine would come to a screeching halt. If I had to guess I would say it would spin up to 200 RPM and then when the clipper would turn on the turbine would instantly stop - not slow down. It was almost like the turbine was shorted.
If we take an additional resistor bank and put it in series with the existing one we could double the resistance and see how that works.
For the Aux1 suggestion we were actually on site to add a 250w heater to the system when we discovered the turbine problem. This will be completed when we replace the turbine on the next trip. It should help use some of the excess power we're generating at the moment as you suggested. We have a half dozen other heaters at the office, so if one doesn't work, we can turn the equipment shelter into a tropical resort!
@dgd - Right now we don't have much load on the system at all. I would estimate around 1 amp constant draw. Over the next few months we will be adding the majority of the radio equipment and increasing the load dramatically. We wanted to have the turbine and solar systems operating for a while to look for problems just like the ones we've been experiencing. Once the final radio equipment is installed and the network is running, any interruption in power would result in multiple communities losing internet and data services. That's a lot of phone calls!
boB the condition 1 in Antarctica is pretty similar to the conditions we face - perhaps not quite that bad though! A student at Memorial University here in Newfoundland did a thesis on small wind turbines used for telecommunications sites back in 2009: www.engr.mun.ca/~sbruneau/research/windresearch/jrthesis.pdf‎ (http://www.engr.mun.ca/~sbruneau/research/windresearch/jrthesis.pdf%C3%A2%E2%82%AC%C5%BD)
It's an interesting read. Aliant, the largest telecom company in the region, could not maintain small wind turbines (Whisper 100's) at their remote sites. The incredible wind speeds and gust forces actually snapped the turbines in two at the mechanical furling mechanism. While the area of study is quite a distance from our operation, conditions are very similar. On the last visit we had over an inch of glaze ice on the tower. In Labrador, towers can accumulate up to a metre or more of rime ice!
For this reason we have tried to find a turbine that has no electronics in the nacelle whatsoever. Just a standard 3 phase pma. We also didn't want mechanical furling due to the problems Aliant faced with them. We settled on the HYEnergy turbines for these reasons, and because they were relatively cheap to test with. I wouldn't want to blow up two or three 1.5Kw Kestrels for the sake of testing!
Devo, that link does not work 404 error?
Got to this page:
www.engr.mun.ca/~sbruneau/research/windresearch/
I have to agree with DGD here.
In my experience it is far better to just shut down the turbine in high winds if power is not needed. Might be a hard current surge while activating the braking but most turbines will not get any speed up while shorted so the blades are stalled and unable to produce enough lift to get moving very fast.
Seems much better than intermittently loading it and letting it fly hard?
No expert but been flying turbines a few years.
Good luck with it.
Tom
TomW - Thanks for your input. We won't be able to shut down each and every turbine in high wind events. Right now we have 7 sites running with turbines, all in different areas. Most of those sites are on remote mountaintops and hard to reach even in summer. The only way we could possibly do it would be with some sort of control system based on actual wind speed.
While we do not need the power right now, we will in the coming months. We would also like to ensure that the clipper can control the turbine without any manual intervention. Discovering this problem now is much better than having it happen on a live site!
Westbranch - The link doesn't seem to work, but the url was right. You're link works better. Thanks.
Is there some setting on the classic that determines when to allow the turbine to spin up? For example if the battery bank goes into float, let it fall to X Volts before allowing the turbine to start up. Maybe we can prevent cycling the turbine on-off when the battery bank is close to full?
Quote from: devo on December 22, 2013, 01:41:12 PM
For example if the battery bank goes into float, let it fall to X Volts before allowing the turbine to start up. Maybe we can prevent cycling the turbine on-off when the battery bank is close to full?
That sounds like a job for the WhizBang Jr...???
Devo,
This slip ring burnout looks like high voltage/high current arcing to the shaft (at earth potential). The reason for this, I would speculate, is a runaway turbine, in high winds, without any effective braking.
I looked at the HY-1500 specs and I see there is no mechanical, ie tail furling, overspeed protection.
According to their web site -
Over-speed control - Electromagnetic & blade aerodynamic braking
The electromagnetic would appear to mean that the turbines 3 phases are shorted together. I cannot see any electronics to do this in the turbine body so it would appear to happen in the HY hybrid controller/inverter they want you to use with the HY-1500
The blade aerodynamic braking is interesting, the design does not look complex enough to have some form of proper blade feathering so I guess it must be torsional twisting of the blades that deforms them and hence they become inefficient and slow the turbine - and probably screech to waken the dead too - something like the swwp Air303 used to do :o
One thing I noticed you said in your original post was that you normally seen over 2500 watts being pushed through the Classic. That, from a rated 1500W turbine with 1800 watt max, certainly seems to show a turbine routinely running way over its design speed.
Although I must admit being surprised that a swept area of about 3.2sqM could extract over 2500 watts but I suppose at 70mph+ winds :-\
So what has happened to the braking?
The blade braking appears ineffective and if you are not using the HY controller then it appears there is no electromagnetic braking either.
SO the Clipper should be taking over the electrmagnetic braking function. It would appear to be NOT actually doing that otherwise you would be seeing the resistor bank heating up and the input to the Classic dropping back.
I don't undertand how the Clipper is just bringing the turbine to a dead halt. If the AUX2 in the Classic is wired to the Clipper with Clipper control setting and AC type PWM then the Clipper should be gradually introducing the resistor bank and slowing the turbine, NOT just bringing it to a dead halt.
I assume you have check all this is wired up as its supposed to be?
My personal thoughts on this configuration you have are that I would not use a turbine such as the HY-1500 at a remote unattended location.
No failsafe mechanical protection such as some form of furling or feathering would concern me about storm/high wind conditions with a runaway and burning up turbine.
The manufacturers web site specs for the HY-1500 describe it as a 'low wind startup' 5 blade design and goes on to show it in commercial use with a 300w PV to drive an almighty load of four 50W led street lights - which obviously on come on at night!
I agree the Clipper resistance may be too low. In tuning my Clipper with 48v 1.5Kw turbine, also a Chinese model but 3 blade, max 2100watts, nice big tail on heavy boom and furls real smoothe, I reconfigured the resistance with 1.3 ohm 1000W types.
Finally I followed ChrisO's advice in why have the turbine/Clipper loaded when you don't need it? When batteries are in float. That was the reason for using AUX1 on a contactor or decent SSR to turn off the turbine by shorting out the 3 phases via the contactor/relay.
One other advantage of this is that if the weather forecast tells you of storm conditions at one of your sites then you simply log into the Classic and set AUX1 to ON which enable the contactor/SSR and effectively turns off the turbine.
dgd
Quote from: devo on December 22, 2013, 01:41:12 PM
TomW - Thanks for your input. We won't be able to shut down each and every turbine in high wind events. Right now we have 7 sites running with turbines, all in different areas. Most of those sites are on remote mountaintops and hard to reach even in summer. The only way we could possibly do it would be with some sort of control system based on actual wind speed.
While we do not need the power right now, we will in the coming months. We would also like to ensure that the clipper can control the turbine without any manual intervention. Discovering this problem now is much better than having it happen on a live site!
Westbranch - The link doesn't seem to work, but the url was right. You're link works better. Thanks.
Is there some setting on the classic that determines when to allow the turbine to spin up? For example if the battery bank goes into float, let it fall to X Volts before allowing the turbine to start up. Maybe we can prevent cycling the turbine on-off when the battery bank is close to full?
Devo;
Pretty sure the Classic can do that automatically by using the AUX 1 per DGD's suggestion:
Quote
Turn off the turbine using a Contactor enabled by AUX1 Float High to short out the three phases.
The Classic can do this shutdown automatically which means you don't have to be there to do it.
Tom
dgd
We don't normally see 2500 watts, but in normal operations we have seen 2500 watts. I just looked at the offline data from the controller and it shows over 2.5Kw of peak power on two occasions, with 1.5Kw on two other days and the rest were well under 1Kw. The highest Vin the controller saw was 142.5v when the turbine was producing 1.5Kw. The last day it produced power the turbine's peak was 136w.
I agree that this turbine isn't the right fit for this area. We need a three blade turbine instead of a five. I'm not convinced a mechanical furling mechanism is good though - I'm not sure it would last.
Like you, I think the braking is causing the issue. It's just a pure guess on my part, but it seems like there is just too much amperage being put through the slip ring when the clipper tries to slow it down. This is why we are looking at the resistance value and trying to determine if it is too low. We've checked the wiring and settings a bunch of times. We even replaced the clipper with another one to see if that was the issue.
Is it possible that the 4Kw load is too large, causing the turbine to basically short instead of slow? A higher resistance would reduce the amount of amperage coming through. You're using 1.3 Ohm's per phase or you rewired it higher? How high should we go for testing? I was thinking of going to 4 Ohms per phase to see how the turbine reacts.
The only other option we've looked at is removing the clipper and going to a full diversion load - i.e. keep the turbine completely loaded at all times. All of our other sites run this way and we have not had a single issue in the 18 months or so they have been running. Granted, this is the first time we have tried a turbine this large. The other sites use 600w units.
I think the blade deformation thing is just to prevent the turbine from physically coming apart. It may prevent the blades from coming off, but I don't think its something I want to try!
Thanks for your valuable input. We'd like to come up with some possible solutions and folks like you are a great help!
I do not think you want to unload that turbine in such a windy site, even if you don't need the power at that time.
First, when is it going to slow down enough to reconnect and second, is it going to fly apart when it is free-wheeling
in such wind ? I don't know if the HY can handle being unloaded in such a case. Maybe, maybe not.
Also, getting 2500 watts out of a 1500 watt turbine is usually just fine. That's why MPPT for wind is so
cool. Let it spin faster but not "too" fast.
As I emailed John today, it may be that the fail-safe on the Clipper is turning on at a lower voltage
than the Classic's Aux 2 is commanding it to be on. The Clipper's fail-safe clipping function is
not PWM and may very well seem like a brake being slammed on. PWMing from AUX 2 is better
when it can be used. Aux 1, which is not as high of frequency PWM is good to use for battery
side diversion control in addition to the AUX 2 PWM SSR/Clipping control.
For completeness here, I will copy and paste some of the email I sent to John a few minutes ago...
boB
****************************************************************************
The Clipper is not supposed to jam on the brakes, but maybe the setting is not right ?
Are you using AUX 2 ? Aux 2 should be more of a higher frequency PWM control.
Now, if your Clipper is doing all off the clipping because maybe its trim-pot is set
for a lower voltage than the Classic is trying to keep it down to, then maybe that
is the problem ? This would be because the Clipper fail-safe voltage trigger is
not a PWM control, but it leaves the triac SSR on longer. I wonder if this might
be the problem ? Next time you are up there, turn up that trim-pot on the Clipper
itself while the Classic is connected and Aux 2 is controlling the Clipper.
Remember that the Clipper AND the Classic can make it clip but the Classic
Aux 2 output actually drives the SSR itself with the internal fail-safe control
of the Clipper "OR'd" with it so if for some reason the Classic doesn't catch it,
the Clipper will. The Clipper should be adjusted to the highest voltage you need.
It can even be set for around 300 volts for a Classic 250 or 250 volts for a Classic
200 but the Classic will not turn on (make power) until the wind dies down to below
250V or 200V.
You can try the Classic's Aux 2 clipper mode or the Aux 2's PV ON HIGH mode.
The Classic Clipper Aux 2 mode also has a high voltage maximum adjustment in
addition to the Clipper mode itself which tries to keep the turbine clipped to just
above what is necessary to keep the Classic in Absorb or Float (voltage regulation)
or even EQ mode.
OK, so if this is NOT the problem (Clipper fail-safe) then it must be that the
clipper resistance is WAY WAY too LOW and needs to be raised. I would first
question the Clipper's fail-safe operation and its adjustment because that sounds
more like what is happening to me. Shorter, PWM pulsing will be a lot more
graceful, but if it is just turned ON for a few seconds, will seem like slamming
of the brakes. That might be OK once in a while, but if it can be PWM'd, then
should be much smoother.
boB
OK, John and Devo have their Classic adjusted correctly I would say.
Let's see if we can keep it from clipping so much. Here's a couple more ideas.
I will say that since the input voltage can be less than even 150 volts that
the Classic might actually want to be a 200 or a 150 which will allow more
output current (power) and then battery side diversion can be added to
help keep the system from clipping so much, or maybe at all.
The output current is set at 50 amps and 2500 watts at at 50 volts is
55 amps. I have a feeling that if the output current is set to more like
80 amps, the battery side diversion will help a lot.
Another thing that will need to be done if battery side diversion is
used, (or maybe not ?), is to adjust the power curve.
In fact, something that we did recently on a 250 connected to a hydro
turbine (24V battery) that was putting out too much power and clipping too
much, was to actually bring the power curve voltages down for a given
output current.
This power curve "de-tuning" can actually be used to help stall the
wind turbine at these higher powers since there you are getting more
power than you need anyway. Sort of a compromise between
direct connected and full MPPT....
It may be a simple matter that it is working too well.
Captain ! She can't take much more !
boB
To "de-tune" the curve, try keeping the cut-in voltage the same as it is.
Turn up the highest curve output current and turn the voltages down.
Not sure where to start exactly, but maybe somewhere around 1/2 way up
the curve and continu all the way up to the very top.
boB
Quote from: boB on December 22, 2013, 07:51:41 PM
OK, so if this is NOT the problem (Clipper fail-safe) then it must be that the
clipper resistance is WAY WAY too high and needs to be raised.
Guessing that was meant to be WAY WAY too
low and needs to be raised.
Quote from: RossW on December 22, 2013, 08:36:58 PM
Quote from: boB on December 22, 2013, 07:51:41 PM
OK, so if this is NOT the problem (Clipper fail-safe) then it must be that the
clipper resistance is WAY WAY too high and needs to be raised.
Guessing that was meant to be WAY WAY too low and needs to be raised.
OOOoooPS !!! Yes, you are right ! Thanks Ross !
Way too high of a LOAD maybe...
boB
Quote from: devo on December 22, 2013, 07:06:34 PM
We don't normally see 2500 watts, but in normal operations we have seen 2500 watts. I just looked at the offline data from the controller and it shows over 2.5Kw of peak power on two occasions, with 1.5Kw on two other days and the rest were well under 1Kw. The highest Vin the controller saw was 142.5v when the turbine was producing 1.5Kw. The last day it produced power the turbine's peak was 136w.
Sorry I worded that badly, I knew what you meant. Even so I would think that slip ring arcing was probably started at one of those high output times. Once damaged the situation would deteriorate even in normal use until the ring's brushes/contacts failed.
Quote
I agree that this turbine isn't the right fit for this area. We need a three blade turbine instead of a five. I'm not convinced a mechanical furling mechanism is good though - I'm not sure it would last.
I always found tail furling systems very reliable, mechanical stressing is probably a tiny fraction of the overall stress the rotating turbine endures..
Electronic/Magnetic and blade twisting schemes for braking as the MAIN braking methods just dont do it for me. Give a furling tail every time.
Quote
Like you, I think the braking is causing the issue. It's just a pure guess on my part, but it seems like there is just too much amperage being put through the slip ring when the clipper tries to slow it down. This is why we are looking at the resistance value and trying to determine if it is too low. We've checked the wiring and settings a bunch of times. We even replaced the clipper with another one to see if that was the issue.
Not sure that this could be the reason for failure but could be. The slip rings are the weakest, highest resistance point in the wiring from the turbine to the Clipper so if there is to be a failure thats where I expect it would happen, apart from a dodgy connection somewhere..
Any evidence of lightening strikes on the turbine/mounting/pole?
Quote
Is it possible that the 4Kw load is too large, causing the turbine to basically short instead of slow? A higher resistance would reduce the amount of amperage coming through. You're using 1.3 Ohm's per phase or you rewired it higher? How high should we go for testing? I was thinking of going to 4 Ohms per phase to see how the turbine reacts.
I ended up with two 1.3 ohm resistors in series on each phase, giving 2.6 ohms per phase. Even now I think this may be just getting a little high and I may look about for 1.1 or 1.2 ohm resistors.
In you case you have 1.6 ohms per phase now and its bringing the turbine to a dead halt. If it were me I would double to 3.2 (or thereabouts) and see what happens.
Quote
The only other option we've looked at is removing the clipper and going to a full diversion load - i.e. keep the turbine completely loaded at all times. All of our other sites run this way and we have not had a single issue in the 18 months or so they have been running. Granted, this is the first time we have tried a turbine this large. The other sites use 600w units.
You mean just connect the output from the 3 phase rectifier to the battery then use a pwm controller (eg C40) to introduce resistive load as diversion?
I have done a similar setup with a remote comms site. A turbine through 3 phase rectifier to battery.
Except I use the wastenot AUX2 of the Classic to connect to a 3phase SSR that has three WW resistors one per phase of the turbines AC legs.
Anyway it seems boB has the problem being sorted, I hope you get it resolved
dgd
Our clippers were shipped with 6 (3ph X 2 in series) .8 Ohm resistors for a total resistance of 1.6 Ohms per phase. I've been speaking to Devin and we're going to double the resistance to 3.2 Ohms per phase to see if we can cut down on the current a bit and perhaps create a smoother landing. I'd still like to know why the clipper was causing the turbine to "clamp the brakes on" though, as I expect the resultant back EMF must be horrendous for a microsecond or 2.
I won't be replacing the load today though for 2 reasons:
1. It's Tips eve
2. The voltage regulator blew on our skidozer and I'm not walking 19KM through the snow. :)
QuoteI always found tail furling systems very reliable, mechanical stressing is probably a tiny fraction of the overall stress the rotating turbine endures. Electronic/Magnetic and blade twisting schemes for braking as the MAIN braking methods just dont do it for me. Give a furling tail every time.
We're always looking at other options. We may just have to try a different turbine with a mechanical furling mechanism. If you had to choose a turbine in the 1Kw range, which would you go with? Bergey?
QuoteAny evidence of lightening strikes on the turbine/mounting/pole?
We haven't seen anything that would be indicative of a lightning strike. I would expect some of our radios would also have been damaged if this had happened.
QuoteI ended up with two 1.3 ohm resistors in series on each phase, giving 2.6 ohms per phase. Even now I think this may be just getting a little high and I may look about for 1.1 or 1.2 ohm resistors. In you case you have 1.6 ohms per phase now and its bringing the turbine to a dead halt. If it were me I would double to 3.2 (or thereabouts) and see what happens.
I'm looking at perhaps testing a single 3.9 ohm 1000w resistor per phase. This would tell us if the resistance/load is causing the appearance of "jamming" the brakes on. In order to test it i'm thinking we could manually charge the battery bank with a generator and charger and see what the turbine/classic/clipper does with the batteries in float. If the batteries aren't in float we won't see the clipper engage. I'd like to actually be on-site when it happens, in case the resistance and/or load is too small. Don't want a fire!
QuoteYou mean just connect the output from the 3 phase rectifier to the battery then use a pwm controller (eg C40) to introduce resistive load as diversion?
Yeah we've done this in the past and it has worked quite well. Although now that i think about it those loads use 3 ohm resistors!
We're open to testing out different things to try to find a solution. I'm not convinced that its a problem with the clipper/classic though. If the 3.9 ohm resistors don't show any change we may just have to look at other turbine options.
I have sent the data and pictures to the manufacturer and they are looking at it as well. I must admit, they have been helpful when things have gone wrong. I don't think they would be a good choice for someone looking for a home turbine, but they are responsive at least.
Midnite has some of the best product support I've encountered in a long time. boB and Ryan have been great answering questions, as well as everyone on this forum. It's nice to see a company that takes pride in its products and really tries to help its end customers. So many businesses these days just want to sell you a product and forget about it!
Thanks again everyone!
Quote from: johnnymac on December 23, 2013, 09:19:29 AM
I'd still like to know why the clipper was causing the turbine to "clamp the brakes on" though, as I expect the resultant back EMF must be horrendous for a microsecond or 2.
This is exactly the reason why I much prefer AC clippers (when possible) over DC clippers.
Turning off at 0 current pretty much ensures there is not going to be an inductive
voltage spike. I think that if 1.6 Ohm per phase is too small that double that is also
going to be too small but I'm just not sure. 10 or 12 Ohms might be just fine.
In fact, if you were getting 1500 watts at 143 volts, that would mean that the load the
Classic was giving the turbine is around 1500/143 = 10.4 Ohms.
I seem to remember you saying you were getting either 1500 or 2500 watts at that input
voltage but I can't seem to find that info right now...
Are you using the stock HY-2000 curve that is in the Classic ? Since your turbine is a 1500 watt
rather than a 2000 watt rated turbine, the current for each of those voltages probably needs
to be lower BUT since (I think) you really want it to stall more than it does, I would leave the
currents in the curve alone and bring down the voltages. Here is the default array of voltages
and currents for the HY-2000 that is built into the MNGP for the Classic.
Cut-in is 62 volts at 0 amps, 66 volts for 17 amps, etc. These values were empirically found
and could be optimized I'm sure. I am sort of suspect at the 17 amps for the first non-zero
current step in the curve but I don't have one of these turbines or the wind to test it if I did.
WndPwrTblVdfltwindmax_2000A[] = {62,66,70,73,77,81,85,89,93,96,100,104,108,112,116,120};//V in
WndPwrTblIdfltwindmax_2000A[] = {0, 17, 20,23,27,31,35,39,44,49,54,60,66,72,77,78}; //I out
Also, maximum current is 78 amps at 120 volts and your current limit is set to 55 amps so that current
limit is going to immediately make the input of the Classic go high and unload the turbine at around
step 11 (54 amps out, 100 volts in) so it will not make it go higher than that step.
I think that if you simply lower the input currents so that they mainly stay below your Classic
current limit, it would help to stall the turbine more and keep the voltage from going so high
which would also limit the amount of clipping.
Of course, to keep from clipping the input, if you could add battery side diversion in addition
to the lower power you will probably get from the de-tuned power curve, that should
keep the clipping way down.
Higher resistance is also something you will hopefully try.
Quote from: johnnymac on December 23, 2013, 09:19:29 AM
I won't be replacing the load today though for 2 reasons:
1. It's Tips eve
2. The voltage regulator blew on our skidozer and I'm not walking 19KM through the snow. :)
Sounds like a couple of very good reasons !
boB
Hi boB,
Devin has ordered some 3.9 Ohm resistors from where ever he found them for our diversion loads on the other systems. When they show up, I'll change over the clipper to the new ones and lug it, via the skidozer hopefully if I have it working, to the top of the hill. We'll then change out the turbine with another spare (thank God for spares) and see how this works.
I'm thinking we should cut out part of the turbine body and put a small "sight" window in there so we can keep an eye on slip ring without taking the darned (I didn't swear yay!!!) thing apart.
He also ordered a 48V charger so we'll bring the battery bank up to float, then we can sit there and watch it to see what happens. I will have to remember to take my kettle this time, as the last time I had my coleman stove, tea bags, sugar, milk, water, but no kettle :'(
Tea time is much more important to me than Devin when we're on site.
Outside of that, I think we're pretty much done until Santa comes.
That said, we want to wish everyone a very Merry Christmas and a Happy New Year!!!
Please be careful, and especially DON'T DRINK AND DRIVE!!! It really is stoopid (2 O's that's really important) you know!!! The life you kill might be your own ha ha ha
Oh.... one other thing.... DGD, with regards to aerodynamic braking, it does seem to work. At one of our sites that has a Turbine with the aerobrake on it, when the wind gusts really hard (120 Kph +++) you can hear the blades trim out similar to a turbo prop. I've been up there in a few storms now and you can watch the current from the turbine as it decreases with the sound change, and the sound is unmistakable. I'm no expert on the intricacies of the blade design, but I do know it sounds like a Dash-8 adjusting their prop pitch as the plane comes in for a landing. The Dash-8 is our most common airplane around here and most everyone who flies is aware of the prop noises. I'm sure with a bit of smoke, you could see the turbulence on the edge of the blade. Tail furling, as nice an option as it is, seems better suited to lower wind areas than we have. As Devin had stated earlier, Aliant (that's our version of Bell Canada) had tried it a couple of years ago with furling tails and did nothing but snap off a bunch of tails. It got to the point that they considered wind power unusable for their purposes. That mindset has not changed for them to this day.
John
Quote from: boB on December 23, 2013, 03:51:52 PM
This is exactly the reason why I much prefer AC clippers (when possible) over DC clippers.
Turning off at 0 current pretty much ensures there is not going to be an inductive
voltage spike. I think that if 1.6 Ohm per phase is too small that double that is also
going to be too small but I'm just not sure. 10 or 12 Ohms might be just fine.
In fact, if you were getting 1500 watts at 143 volts, that would mean that the load the
Classic was giving the turbine is around 1500/143 = 10.4 Ohms.
An interesting calculation :)
When I did this some time ago for my turbine I did it differently
So for 1500watts at 143 volts that gives amps as 10.4
So classic R is 143/10.4 or about 13.5 ohms
V on each of 3 phase inputs is 143 *.74. = 102v
So to load each phase to same as Classic needs about 10 ohm resistors
So I would go slightly under about 8.5 to 9 ohms
Did I get this wrong?
My turbine is 103v at 1600w as it has 3.2 metre swept dia and spins much slower at similar power from high speed 2metre hy1500
(103*.74)/(1600/104) or 75/15 = 5 ohms per phase or 3.5 to catch over 1600w events..
It seems to work for me but then my calculation may be too simple or even just not the way to go..
Happy Christmas
Dgd
Quote from: dgd on December 25, 2013, 04:54:15 PM
Quote from: boB on December 23, 2013, 03:51:52 PM
This is exactly the reason why I much prefer AC clippers (when possible) over DC clippers.
Turning off at 0 current pretty much ensures there is not going to be an inductive
voltage spike. I think that if 1.6 Ohm per phase is too small that double that is also
going to be too small but I'm just not sure. 10 or 12 Ohms might be just fine.
In fact, if you were getting 1500 watts at 143 volts, that would mean that the load the
Classic was giving the turbine is around 1500/143 = 10.4 Ohms.
An interesting calculation :)
When I did this some time ago for my turbine I did it differently
So for 1500watts at 143 volts that gives amps as 10.4
So classic R is 143/10.4 or about 13.5 ohms
V on each of 3 phase inputs is 143 *.74. = 102v
So to load each phase to same as Classic needs about 10 ohm resistors
So I would go slightly under about 8.5 to 9 ohms
Did I get this wrong?
My turbine is 103v at 1600w as it has 3.2 metre swept dia and spins much slower at similar power from high speed 2metre hy1500
(103*.74)/(1600/104) or 75/15 = 5 ohms per phase or 3.5 to catch over 1600w events..
It seems to work for me but then my calculation may be too simple or even just not the way to go..
Happy Christmas
Dgd
Yes, Happy Christmas DGD !
No, I think your calculation is OK. Remember though if it is 10 Ohms phase to center point that this will
be two times 10 Ohms in series from a phase to phase standpoint. BUT, there are 3 phases so it's
actually lower than this, on the average.
In addition though, the 10.4 Ohms I came up with was just an equivalent resistance presented by
the Classic for 1500 watts at 143 volts. If the wind gets higher, then the resistance from a clipper
will want to be lower because the voltage will rise from this starting point.
I like to reduce my minimum amount of resistance necessary for safe clipping by approximately two
to allow for higher winds. If you have any kind of PWMing, then this half resistance can easily
be made an equivalently higher value with that PWM.
It sounds like in the case of our Canadian friends here on their very windy mountain-top site,
that the resistance of their Clipper is WAY WAY too low, IF it is what is causing the slip-ring
burn up problem. It may of course be something completely different and not because of
too low of resistance load but I just don't know yet.
Ideally, a good PWM'd Clipper can take a much lower resistance than necessary and make it
almost any resistance higher than that for variable Clipping. Of course that ideal-ness does
not exist in reality.
boB
I am not a wind expert, but I do have a couple of observations to make on this.
Take a look at the picture here. It is of the slip ring assembly on our turbine under development for the US Army.
You will note that there are two sets of brushes for each slip ring. You will also notice the plastic dividing discs between each slip ring. They have a long overhang to help eliminate the carbon dust from shorting one slip ring to the other.
Now take a look at the slip ring assembly on the broken turbine. It looks like a single set of brushes. I do not see much separation between brushes either. The carbon dust that accumulates around the slip ring area is conductive. Given enough dust, voltage and current, bad things can and will happen. That is what drove our design. I suspect the slip ring assembly on this turbine is just not up to the job being asked of it. One thing that might help would be to detune to power curve such that you keep the voltage lower and thus the speed lower and thus the current lower. See where this is going? Reduce the load on the slip rings. I suspect the same thing would happen to these slip rings with or without the Clipper and classic, but with the Classic and Clipper you have a chance of limiting the output power to save the brushes.
Good luck, this stuff isn't easy.
(http://farm3.staticflickr.com/2811/12154044855_fed431c50d_z.jpg)
A little update for everyone. We replaced the 1.6 Ohms per phase 4Kw load with a 4 Ohms per phase 3 Kw load.
We kinda have it working TOO well! Notice the temperatures on that picture. Things are soon going to start catching on fire. Winds up on that mountain are probably reaching 170 - 190 Km/hr today. Wind warnings are in effect everywhere from the weather office. Here at home I'm seeing gusts past 150Km/hr at sea level. This site is at an elevation of over 500m!
One question: If we turn the mode to OFF on the wind classic will that short the turbine and stop it, or will the clipper just continue to dump?
Right now it may come down to a decision between blowing up the turbine or allowing the telecom shack to catch fire!
On another note, boB, we're certainly stress testing the clipper and classic!
I'd love to see just what kind of power this setup is actually generating. I expect its 3Kw+ being dumped into a building that's 8' x 8' and insulated like crazy.
At what temp will the PCB melt? 100C? 110C? At some point the thing will just explode from the heat eh?
We're not even sure we can get someone up there to open the darn door on the building and let some cool air in.
devo, I know it may be too late this time, but is there any possibility to automate the venting, like they use in greenhouses? I believe they use a small opening device 'powered ' by a cylinder.
http://www.groworganic.com/automatic-vent-opener.html
Ryan or Bob can tell you how to reduce the speed of the turbine although since the resistance was changed, it may not slow the turbine down. The battery temp is disturbing. The rest of it is ok. Circuit boards are rated for 130C.
I will see if they can chime in here.
This is a condition that we would like to see automatically turn down the speed of the turbine. Sustained high wind conditions should be able to be identified by the Classic and dealt with, but it is not automatic yet.
After looking at the meters again, I do not think the turbine can be slowed down. The Classic is in float. That means it would have sent a signal to the Clipper to bring the speed down so the voltage is just above float. I see the voltage is 194 volts. It may be that the 4 ohm resistors are too much resistance to control the stator. Just a guess, but that is what it looks like to me.
What I would do at this point is go to Aux2 and turn it manually ON and see if the Input voltage drops? If it does drop a lot life should be good. If it drops very little to none than the clipper is already doing all it can to slow the turbine. I am not worried about the Classic and heat so I would not turn the mode off.
I assume there is solar on site to? And probably no way to turn that off? I would say that in the future you should have the wind set to a higher voltage than the solar.
So what this shows me is on a remote site a Exterior mounted diversion load would be an asset.
Other than turning the clipper full on or turning some load on to actually load the turbine down I am sort of at a loss. You could flatten the wind curve way down to try and stall the turbine that may help but only as long as there is a load needed.
Thanks for the replies guys! I think we've dodged the bullet this time ... the wind has subsided and everything is back to normal.
We really need to get the environmental monitoring system installed at these sites so we know what's happening outside.
@Westbranch - We thought about using some industrial louvers and fans about 6 months back, but we haven't been able to generate any substantial heat in the buildings until now. The only concern we have with louvers, or any other mechanical opening, is that we would be letting the wind inside the building. By allowing the wind in, we may not have a problem with heat, but the building may end up at the bottom of the mountain!
@Robin - Our big concern was the classics themselves. We weren't sure how much heat they could take before meltdown. If they can handle 130C we should be okay. The temp peaked at about 90 - 95C on the PCB and FET. The batteries are rated to 50C, but I don't know if they can take much above that. The rest of our electronic equipment is rated to 60C, so it should be fine. The 194V was a peak that I managed to catch while watching the local app. Once I did see the voltage hit 200v, but only for a second. That's what we have the clipper set to as a maximum for testing.
@Halfcrazy - I didn't get a chance to actually try to manually engage the clipper. I think there MAY have been a few volts drop if it was engaged, since the input was held fairly steady around 170 - 180V with peaks to 194 - 200v a couple times. If there was any capacity left in the clipper it wouldn't have been a lot. We've already discussed adding an external dump load to get rid of the heat outside. That might be one option. The other option we are looking at is adding a 1Kw split mount air conditioner / heater in the building. Our concern is during the summer months when it is 25 - 30C outside and the clipper starts dumping 2 - 3Kw of power into the resistors. We could overheat everything, or start a nice little fire! The AC unit could take 1Kw of energy from the system, reducing the amount of clipping, while also cooling the building without opening the building up to the wind.
There is roughly a Kw of solar at each of these sites as well. Today was too overcast to generate much power, and with the batteries in float i imagine the solar classic would just open the panels and not let them produce. Is this correct?
I think we can safely say that 4Ohm, 3Kw load on a HY-Energy Hy-1500 turbine will generate some serious heat!
Here's the site we're talking about:
(http://farm4.staticflickr.com/3670/10301875003_ab20961bc8_z.jpg)
(http://farm6.staticflickr.com/5493/10301729865_9e1f9bbcb4_z.jpg)
(http://farm4.staticflickr.com/3811/10301666394_9e258e11eb_z.jpg)
Yes I like the idea of the Mini Split set to Auto. On a day like today it would cool the building and load the battery. Win/Win. I would also suggest getting something like the classic on the PV so you could manually shut it down in a case like today. And then maybe use an Aux from that Solar Classic to hold a SSR for the Mini Split on maybe? So you could turn it off remotely if ever needed
Ryan
that Mini-split is a real good solution, 24/7/365.. since that container is exposed and probably can heat up somewhat in winter too on a bright day. You could even use it to pull down the battery if you found it never really cycling to you targets, that is assuming the Nl-Ld weather cooperates... ::)
I don't know what Classic you are using? The Clipper should have brought the turbine down to 65 volts or so if you have a 48V battery bank. It did not do that. The question is did the Classic send a signal to reduce the voltage? Was the Clipper able to bring the voltage down? If you are using a Classic 200, I would be setting the Clipper for about 160V. The turbine isn't making any real power above 100 volts more than likely. We need to do a better job of integration between the Clipper and Classics. We also need to add a storm mode that acts automatically. We also need to identify which resistor bank to use with more turbines. Unfortunately that would require a sample of each turbine and a wind tunnel. We are building a wind tunnel that will put out some serious wind, but without each and every turbine, it is tough to recommend the correct resistor.
Back to your problem.....if the Classic and Clipper were communicating correctly, then the resistor bank may be too high of ohms. Then again, it might be that the stator is not strong enough to be controlled at those wind speeds regardless of the resistance. All stators will have a limit to which they will break free even if shorted out. Too bad the manufacturers don't tell you that spec. Can you ask them?
By the way, the fiberglass boards are rated for 130C. The fets should not go over 95 to 100. I think the Classic was unloading to keep from dumping more power?
Hey guys, just wanted to post a little update on our classic/clipper setups.
For the past year this site has been running 24/7 on wind and solar, with 100% uptime. The two Classics and the Clipper perform flawlessly. The battery bank is consistently in float. All of our sites now run Midnite Classics exclusively.
The Clipper has certainly proven its reliability. These products can't be beaten for quality.
Any pics? Specs...? ;)
I don't have any pics handy - we haven't even visited the site in 6 months! A couple of pictures of the box/panels/tower are posted earlier in this thread.
The site runs on four 250w panels, a 1500w HYEnergy wind turbine, two Classic 250's, a 4KW Clipper and eight Rolls-Surrette S12-240AGM batteries. The average load at the site is only about 50w, but it's a critical segment of our network.
I'm building another identical setup for another site right now, so perhaps I can post a few pictures of the completed wiring in a few days.