Hey folks!
We're using classics and clippers to control some off grid wind turbines, but would like to have the option of remotely shutting down the turbines before really high wind events.
I've been looking at different solutions using 3 pole contactors. I came upon a an old graphic that Ryan had created showing a basic "clipper" using a contactor. In that diagram he has the wiring from the turbine hooked to a rectifier, but on the input side of the rectifier he has additional wiring ran to a 3 phase contactor. Operating this contactor shorted the turbine.
Can this same wiring scheme be used between our turbine and clipper? That is, can we run the input from the turbine into a 3 pole normally open contactor, run jumpers from there to the input of the clipper and then use the contactor to short the turbine? Will that work?
My first reaction was that we need to use a second contactor to disconnect the clipper. Perhaps I was wrong.
Thanks,
Devo
Quote from: devo on January 03, 2018, 10:43:03 AM
I've been looking at different solutions using 3 pole contactors. I came upon a an old graphic that Ryan had created showing a basic "clipper" using a contactor. In that diagram he has the wiring from the turbine hooked to a rectifier, but on the input side of the rectifier he has additional wiring ran to a 3 phase contactor. Operating this contactor shorted the turbine.
I can't comment on the interaction with the clipper, but just a general observation - if you have the three phase wires from your turbine, you only need a TWO pole contactor to do the job. Contact 1 across phases A-B, and contact 2 across phase B-C or A-C, doesn't matter. When the relay/contactor closes, all three lines are shorted together.
My only concern would be eliminating the Clipper from the equation. I've had my Bergey XL in "braked" mode (shorted together) spin up to the "farts of the gods" level...blade tip flutter, the helicopter rotor sound. That means the turbine and wire to the brake circuit breaker have become the clipper and are heating up.
I think a more appropriate remedy might be to have the clipper be fully engaged/on before or during the events. I just trip the aux 2 Clipper function to "on" when I need braking or near braking enabled. Perhaps a 12 volt dc source (not from the Classic) on a controlled relay/contactor that is parallel connected to the clipper might work? If it's regulating via the Classic the exttra source would be disabled (either normal operation or "clipping"), if you want the extra source enabled remotely (however that's done) the classic regulation would be moot.
Maybe the Gougen gents will have some idea if this is feasible. Their input is always appreciated by the hoi poloi.
Ralph
Having seen a turbine explode while I was next finger over (Sail Boat in a slip [tied up in a marina] boat beside) had one up & was sounding like a finger wizz whistle from the 50/60s . Sure enough it blew apart as sails were unfurled & dingy s flew through the air .
I lived onboard 1985-96/99 .
What I see is an TWO pole contractor / heavy relay that also has a red LED light tell you its on via a manual special switch .& as Mr Ralph Day posed , turn on full clipper B4 & check to see the blades are stopped or real slow & then flick switch to stop .
Less breakage .
led & special switch to remind you
VT
Thanks for the suggestions everyone.
I'm still unsure as to the correct method to wire it. Using a two pole or three pole contactor isn't really the important bit - what i'm more interested in is clarifying if the "stop switch" needs to disconnect the clipper before shorting the three phases.
Can the "stop switch" simply short the turbine while still connected to the clipper, or does there need to be a second contactor/relay/etc to disconnect the clipper before the first contactor shorts the phases?
Quote from: devo on January 08, 2018, 04:47:15 PM
what i'm more interested in is clarifying if the "stop switch" needs to disconnect the clipper before shorting the three phases.
This would be dangerous. Adding anything in series with a turbine (wind or hydro) has the potential to be catastrophic if a contact goes open, or if using N.O. contactors and the coil burns out.
Quote
Can the "stop switch" simply short the turbine while still connected to the clipper, or does there need to be a second contactor/relay/etc to disconnect the clipper before the first contactor shorts the phases?
From the manual for the clipper (found online at the midnitesolar website) I don't see anything inside it that would suffer from having its inputs shorted. Moreover they specifically say you can parallel two clippers for greater capacity.
Also, that "when the slider on the side of the Clipper is in the stop position the input voltage is held to zero volts through 50A circuit breakers" so I'd be pretty confident shorting the inputs when the turbine is stopped or going slowly will be fine.
RossW, what i had in mind was using a normally closed contactor and a normally open contactor together. You can get them with the interlocks so they both activate at the same time, but one can't activate without the other.
I think I'll give it a shot with just the NO contactor on the turbine side of the clipper. We'll see what happens.
Then end goal here is to create a system that will automatically shut down the turbine in high wind events. We can communicate with the Classic over MODBUS, so it should work - at least in theory. The system will monitor an anemometer for wind speed. If winds become too high it can activate Aux2 ON and slow the turbine. Using the input voltage at the Classic we could gauge the turbine speed. Once its at a safe speed, activate Aux1 to trip the coil in the contactor, stopping the turbine. When the wind has slowed for a period of time, release the brakes and put Aux2 back in auto mode.
Any ideas on how slow the turbine should be going before flipping the brakes on? I've hit the breaker on the Clipper while the turbine was producing, but not in much wind really.
apply the turbine brakes sequentially ?
It is perfectly fine to short the 3 phases on the turbine side of the AC clipper as its isolated by the rectifier so the second NC contactor is NOT needed.
FNG
Quote from: FNG on April 04, 2018, 04:50:32 AM
It is perfectly fine to short the 3 phases on the turbine side of the AC clipper as its isolated by the rectifier so the second NC contactor is NOT needed.
FNG
That's electrically fine, but I was concerned about "slamming"on the brakes and breaking something in the turbine, a blade or bolts somewhere
We just endured a storm of the year here. With the clipper engaged ("on") no slowing down, only lots of heat. I didn't even try braking, just listened to the rumble for hours (intermittently of course). Glad I got the clipper.
Ralph
Hi,
I don't know that you said what type of turbine that you had, so this may not be appropriate, but we've been using a "power furling" approach that has proven to work very well. Basically we are using the Aux1 relay set on PV V on Hi to monitor the voltage. If it gets too high, for too long (and you can adjust these parameters), it will furl the tail and softly pull the thing out of the wind.
We had hellish winds last week. When I want to manually shut things down - because the winds are too rough for liking, or if the PV is ample, as on many summer days - I manually trigger the Aux relay which folds the tail, and then close in the load bank ('clipper' in your case. It is all very soft which I like. You can also have it reset when the voltage drops to a level that you like. Going the other way - I can unfurl the turbine after a storm, with my slippers still on, and ~30-45 seconds later we're producing power.
More details here:
https://www.fieldlines.com/index.php/topic,149230.msg1043224.html#msg1043224 (https://www.fieldlines.com/index.php/topic,149230.msg1043224.html#msg1043224)
Good luck ~ks