Building a Homemade Wind Generator Brake

By , October 10, 2012

Our home wind generator features a charge controller with a regulation feature, which the manufacturer claims eliminates the need for an actual brake for the mechanism. When charging reaches a preset voltage level, the prop slows itself, and will eventually stop, if the wind is not too strong.

In practice, I find that a brake is an essential back up to this feature. There are many situations when the generator must be stopped completely. To do this, I built my own brake.

brake switch insides

It’s nothing more than a simple double-pole light switch. Yellow tips are capped pigtails coming off the main lines. (Photo: Mark Zeiger.)

To stop the generator one literally must short it out by connecting the three wires that deliver the unit’s AC current to the charge controller. By splicing into these three lines and leading each splice to a switch, a brake is created.

To make mine, I looked at the old charge controller for the system, which incorporated a brake switch. I have two, one that works, and one that had been destroyed in a catastrophic short when the previous owners braked it in too much wind. Their switch is simply a double-pole light switch. Each wire is connected to a post, with an arc of wire connecting the 4th post. I duplicated this, then turned the switch upside down. It’s always “off” according to the switch, unless we turn it “on,” joining the three lines and shorting them out.

I took these photos when the switch failed, and I needed to repair it. It failed because I used the “back wire” ports to connect my wires. I have learned that back wiring is now considered unreliable, even unsafe! Few switches have back wire ports now; side wire connections are all that remain. I found that by switching the wires to the side wire posts, the failure went away, and the brake works better than ever before!

wire extensions

Extensions connected, bent double to insert into split bolts to connect to pigtails (Photo: Mark Zeiger.)

For practical reasons, I added smaller gauge wire extensions to my pigtails. I used split bolts to attach the extensions to the larger pigtails, then ran the extensions into my switch box.

enclosed brake switch

Closed up neatly, ready to stop the generator! (Photo: Mark Zeiger.)

We have found that clear labeling is essential to operating the brake. I’ll explain that, and offer our solution, in a future post.

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