A bit wary about shorting out

[jabba]

I have a treadmill motor on my windmill. I built a mechanism on it so that I can make it hold over on full furl in high winds. I know that shorting out the motor will bring the blades to a stop, but I'm afraid of doing thyat, and burning out the motor. Am I right in thinking this way?

[hayfarmer]

one of my mills is an amtek micro , on it 2 years ago lost 1 set of blades  (ripped off ) made of aluminum and 1 of galvanized steel  blades to wind speed of 75 mph that I didn't turn on the stop (short)

switch to stall the mill.since then I have been running smaller galvanized blades length 1/4 less and width 1/5 less with no problems.

last week we had a storm around 50 mph and I threw on the stop switch before the winds picked up and it did just that,the problem was mill turned 180 away from wind

and the blades weren't moving so they bent.   Upon further thought my game plan is leave mill alone unless forecasted winds are much greater than 50 mph then I will tilt

the tower down and may try composite fiber blades.

good luck and here's is a quote from a wise very wise man:

>   "And if you don't have busted wind turbines, then you live in a poor wind area." (Cris Olson)






scotty I need more power   


hayfarmer

[Flux]

It's bad practice to short any form of dc machine when its running, only the internal resistance limits the peak current. For a small machine like an Amtek there may be enough internal resistance to get away with it. Trying this on any larger dc motor or generator will flash over the commutator and damage the brush gear, it should be avoided.

Shorting when stationary to act as a brake against start up during erection is fine. You may or may not get away with leaving it braked in a gale depending on the blades but I wouldn't want to assume that it was ok.

Considering these things were designed for an entirely different duty and they are very much abused in normal operation as wind generators they cope remarkably well but don't push your luck. I really can't see why they are left to all nature can throw at them, larger machines have to be furlled and there is no real difficulty in making furling schemes for smaller ones.

It's probably only the nature of the blades used that lets these things survive in storms and the fact that they are small and small things are inherently more self protecting.

Flux

[jabba]

Wo hayfarmer! That's pretty nasty looking. Goes to show how fragile things are against an angry wind. I was hoping to leave mine up during a storm, but maybe that might not be possible.

Fluxx, the blades are wooden ones, and with my system holding the tail at full furl during a storm, they *should* have a good chance to survive, but as I said, it might not work out that way. The next storm will tell a lot.

 I was thinking that shorting them out was a bad idea alright. After all the hassle of building the whole lot, I don't wnt to kill it by shorting it when I don't need to.

[hayfarmer]

jabba ,do you have a pic of your mill? did you build a  furling tail for it.If you did sure would like to build one for amtek,my H.F. worm gear winch could use the break,have very


high wind area.if you could post a pic it would be much appreciated. thank you kindly.


hayfarmer

[jabba]

I have no pics yet, hayfarmer. It's only up a couple of days. Was going to take a few today, but it's a terrible day outside. Windy, but more importantly, very rainy. All day long. Tomorrow is supposed to be good, so I'll take a few pics and post them up. I did build a furling tail for it. Tbh, I kinda guessed that bit, and did some trial and error to get it to furl at the right time.

[jabba]

Here are some pics I took.  You can't really see the tail too well. The trees are a bit close to the blades , but I don't own the property where it's located, and I can't chop down everything around it. Best I can do is keep them trimmed. Having said that, the prevailing wind is from the direction where there are no trees or anything. I meant to take a pic of the view from there to give you a better idea of where it's located in relation to the surrounding area.

Also pictured is my vandalised solar panel. I put silicone on it as soon as I discovered it, but it was broken for a good while before I knew anything about it.

The whole reason why I built this windmill is to run a broadband repeater. That's the box on the pole. The two mesh aerials receive  and transmit the broadband signal from about 7 miles away down to my house about a mile from the mast. It's the only way I can get broadband as it's not available in the area. I'll try and get better pictures later

[hayfarmer]

jabba,thanks for sharing the pic,s .I guess that will be my next project making a furling tail for my amtek mill, winds too extreme to keep replacing blades had gusts to 60 mph

today.wont get to work on that project for a while. sorry to hear the vandals wrecked your solar panel.that was mean...just out right mean.may have to put it up out of reach say

15 feet up tower for security and maybe wire mesh under side of it for rock protection.


keep up the good fight am interested to hear more about your broad band repeater system.


hayfarmer

[jabba]

Yeah, hayfarmer. Was thinking of doing something like that. I'll take more pics, with some close ups when I take the mill down to see how it's performed over the last few days

[Madscientist267]

Jabba -

Definitely don't worry about shorting causing any problem with the panels at least.

The turbine is of course a totally different animal, and I can't speak on that.

FWIW

Steve