Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28
Posted: 11:11pm 02 Feb 2011
Copy link to clipboard
Print this post
I have nearly finished Gizmo's TL084 controller and made 8x 80W each heating elements rated for 15V, connected in parallel for up to 640W dump load. This is for the 300W (500W max) Chinese turbine I am converting to downwind.
Glenn shows his controller switching generator directly to the dump load, however everywhere else I saw the controller usually switches dump load that is fed from the batteries. Which makes sense to me, as we have known voltage etc. What I don't understand is if we connect generator directly to the heating elements, how do we know what voltage will be across those elements, given that freewheeling voltage can be very high and batteries are the only thing clamping it. We now take batteries away and connect it to the load directly....I probably don't know enough about this, that's all.
Also as my turbine has no furling it will rely on loading it to control overspeed. I think until I get a smarter staggered load controller I will just have a few switches to turn on more elements as required, i.e. let's say 250W for usual conditions (300W turbine), but can increase it to say 400W or 500W if required - sudden storm and mill is still up, for example. What happens if I load 300..500W turbine with 640W load at once, will it burn rectifiers or generator itself or just stall?
Hope this makes sense, I just need to understand how this all works and what's the best strategy in your oppinion.
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 04:46am 03 Feb 2011
Copy link to clipboard
Print this post
Hi Tomasp
I use mine across the batteries to maintain a constant voltage, this worked well for me, it is set to dump at 27.5 volts at the moment with both wind and solar, Dump is to a GTI, with my battery pack there is enough capacity to even out loading, with yours it would be a good Idea to place a shorting relay in the mill as that was what the original regulator did, I am playing around with a remote gate opener switch (radio link) switching is powered by a bleed rectifier of the three phase, in your case you have dc available at the mill, so shouldn't be a problem. With non furling you need an effective brake or very strong construction to allow runaway without self destruct.
All the best
Bob Foolin Around
tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28
Posted: 08:57am 03 Feb 2011
Copy link to clipboard
Print this post
Thanks as always, Bob,
What you are doing makes sense - I will probably also switch it over the battery. In that case I know my dump load will work, although it might bring volts down a bit too quickly (being 2x more powerful than the mill) - probably should decrease it at least to the "max" rating of the turbine.
You read my mind about remote shorting, I just need to find control block small enough to fit into the housing. In the meantime the plan is to take tower down on any news of really bad weather, other times hopefully loading will be enough.
Cheers
P.S. Just tried switching on TL084 controller - no signs of life. Checked and have no output voltage from the regulator - off to get a new one tomorrow. I wonder if it shorted out somehow. Probably have check the board once again.
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 10:24am 03 Feb 2011
Copy link to clipboard
Print this post
Hi tomasp
You may find that the mill will do more than its rating in strong wind, my old 500 watt machine will go to 1200watts in gusts but the batteries should smooth out the excess to some degree. the little gate controller is quite small so it should fit in, if not a jiffy box could be sealed up OK.
All the best
Bob Foolin Around
niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331
Posted: 11:28am 03 Feb 2011
Copy link to clipboard
Print this post
hi Tomasp
i,m not sure about this but if the regulator shorted you,d probably get near the input voltage showing up on the output side .....if its damaged it also might run hot as well
could maybe be an open connection on the the i/p pin or ground pin ?
niall
tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28
Posted: 08:57pm 03 Feb 2011
Copy link to clipboard
Print this post
Found the problem - I did not cut the tracks underneath the opamp. May I suggest to Glenn changing the picture a bit, because it is not obvious (or make a note in bold in the text). I found some older postings of people having the same issue.
Anyway, regulator works, but I think the opamp is toasted. All diodes checked OK, so I will replace opamp and transistor (just in case) and should be sweet.
Bob, where did you get your gate controller? The only similar thing I could find was universal 4 channel remote controller from Soanar for $54 or just getting a car alarm from an auction (probably around $40) but these usually are a bit large to fit into the housing - which would be ideal. On the other hand it might not be possible now that I have 3 bridge rectifiers mounted there. Need to ponder on that more.Edited by tomasp 2011-02-05
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 10:03pm 03 Feb 2011
Copy link to clipboard
Print this post
Hi Tomasp
I got mine on Fleabay for $16 from Hong Kong it is a single channel thing with just open and close, so would work a relay for the three phase OK, I got 2 electronic relays for 10 bucks each, 40 Amp AC with DC control 5 volts once again on fleabay.
Did you use a socket for the Op amp? as I found that soldering them in to the board I buggered a lot, but the socket isn't static sensitive, just have to short out the pins on the socket with a bit of al-foil when inserting the IC to avoid nasty accidents. Same with the transistor I wrap a bit of fine wire around the three leads.
All the best
BobFoolin Around
tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28
Posted: 10:52pm 03 Feb 2011
Copy link to clipboard
Print this post
Thanks - will have a look for that remote.
Yes, I am using a socket - good idea about the static, will use that on my new parts :)
Anyone else would like to voice their oppinion on the size of the dump load?
Thanks
tomasp Newbie Joined: 20/10/2006 Location: New ZealandPosts: 28
Posted: 01:20am 04 Feb 2011
Copy link to clipboard
Print this post
Controller is working now perfectly. I couldn't get TL084 this time, so put in TL074 (a "better" version twice the price)
Problems I encountered were all mine.
1. Tracks not cut behind the op amp due to not-so-obvious picture
2. Missed to solder one of the op amp pins
3. when I cut tracks the knife slipped onto neighboring tracks as well, cutting them in two instances. Barely visible!
Hopefully this will help someone.
Cheers
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 01:11pm 04 Feb 2011
Copy link to clipboard
Print this post
Regarding your item No3. (knife slipping), it is not a good idea to use a knife at all when cutting tracks on veroboard. So, how to cut them instead?
Easy, use a drill bit (~4mm) in a hand held mini chuck or get that proprietary gizmo that looks like a straight flute drill with a plastic handle.
You will wonder ever after why you even bothered using a knife .
The drill point is inserted into a hole where you want the track cut and then twisted gently until you have a small countersunk depression and all traces of the track have gone. It pays to check with a magnifying glass as sometimes a hairline swarf stays behind to haunt you later.
Best practice this first on a piece of scrap veroboard until you get the idea, its easy peasey ever after.Klaus
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
Print this post
.
to haunt you later.