Q: How does a brake work on the wind turbine?

foolios

I got one of those 400w wind turbines off of eBay for $125 to play with.
Is braking a shorting of the three AC wires? I was wondering if I could create one from a shorting block that I already have if that's the case.



Thanks in advance for any information.

BB.

From what I can make out on the label, yes, it shorts the three green wires to brake the turbine.

There is not much in the way describing if this controller actually controls the battery charging voltage (other than stopping the turbine by shorting the AC windings at 15 or 30 volts -- for a 12 or 24 volt battery bank). Seems to be OK as a starting point for flooded cell lead acid batteries. If you lived in an area with constant high winds (many hours/days straight)--I would be monitoring the battery bank voltage and state of charge (and electrolyte levels) to make sure you don't bake the bank.

Paralleling this with other charging sources (solar/AC/another wind turbine/etc.) seems to be a reasonable installation (assuming the wind controller is properly designed and constructed internally). Placing a fuse/breaker between the + battery and + controller connection would be recommended (20 amp maximum breaker/fuse for 16 amp / 12 volt operation. 15 amp fuse/breaker for 24 volt--My personal suggestion).

YT-122 400 Watt Waterproof Wind Turbine Controller
Rated working voltage: 12V/24V
Maximum charging current: 16A/10A
Static power consumption: 6 mA (from battery bank?)
Protection Class: IP67
Braking Voltage: 15V/30V
????
Wiring Diagram indicates:
Green Green Green Black and Red

-Bill "your translation may vary" B..

mike95490

You should be careful when making an electric brake,  If you slam all 3 wires shorted at once, you can spin the rotor off the shaft or break a shear pin.   Either engage a single winding at a time, a couple seconds apart, or use some sort of ballast resistor to slow it down before applying the stiff electrical brake.   The smaller they are, the less important this is.  Sometimes the electrics won't provide a sufficient brake, and you need a mechanical brake too / instead .  fun with wind !

foolios

Thank you both so much for the information. I will heed all those instructions. I was just wanting to use it for keeping the battery levels up a little during the night. It seems that these small 400w chinese ones only put out about 200 watts. I've got a 24v battery bank with 210AH worth of storage. It usually takes about ~100 watts at night to keep the batteries up.
I will implement the brake and the fusing. Still wondering if I need to worry about a dump-load. The batteries are grid-tied so I'm thinking when it says the batteries always need to be under load that this would be a constant load. That if the voltage were to ever rise, it would dissipate via the inverter to the grid. So I'm still looking into the whole dump-load thing.

mike95490

With wind turbines - you can't be too safe or redundant.  You need a dump load in case the grid goes down.  

As in the case of my folks last week in the 3rd No'easter this month.  60mph winds, and the grid goes down.

With no dump load, or automatic brake, the turbine WILL overspeed and start shedding parts

foolios

Glad I asked. You can never think of every situation. 
Thanks for the enlightenment.