Lowering the wind turbine adding a brake

I have read that connecting the wires would immobilize the turbine for it's protection in hurrucaine winds.

I will be building a PMA which will have 3 wires going to a rectifier which will convert it to 2 wires, 12 volts.
If I wanted to install a brake for stopping the turbine so I could bring it down which wires would I short?
Would they be:
1 before or after the rectifier
2 which wires to short

Thanks again for the help.
It sucks being a newbie!

No expert but it can be either side of the rectifier.
I have my heavy gauge pos and neg cables connect with crocodile clips so I can quickly detach and short to a standstill.
Be warned though they stop really fast! :shock:
Mine stop with a thump but as I'm using steel blades its not a problem.
Other blades might shear clean off so if a controlled stop can be made its better.
Something with a varying load. :?

No expert but it can be either side of the rectifier.
I have my heavy gauge pos and neg cables connect with crocodile clips so I can quickly detach and short to a standstill.
Be warned though they stop really fast! :shock:
Mine stop with a thump but as I'm using steel blades its not a problem.
Other blades might shear clean off so if a controlled stop can be made its better.
Something with a varying load. :?

Good point Shawn,
I guess a heavy duty potentiometer on one of the shorted leads would be a help.

Shawn - Ouch! Just shorting like that while the blades are moving means all the rotational energy, not just above the cutin RPM but everything down to zero RPM, is instantaneously spiking your genny coils.

Just musing aloud about things, presumably by the time one says Hey I Need To Stop This Turbine, the controller's already going to have switched in the normal divert load. So what if one had a second divert load connected across the turbine output (after the rectifier if the diodes can handle the instantaneous amps, before them if not) which one could manually switch in for emergencies? It wouldn't have to stop the blades as such, just put them into stall - I think!

Obviously if before the rectifier, you'd want to load all the phases the same and at once. I have a mental picture of three industrial-size power resistors in star config. Wonder how you'd switch them in all at the same time? Three SPST's in a row, I suppose.

hi Cabrera

shutting down (emergency) can be tricky ..using the rectifiers (as was pointed out ...) as a load for this means they have to able to withstand the load induced upon them during a sudden brake ...if your worried about this you can make up a basic resistor using strands of stainless steel rope/wire to shunt the load



if you used 3 sections like these this (play about with it ) in star ..it takes the sting out of shorting

this lets you stall out the mill on the ac side ..then apply a full short to stop the alt running out of stall ..its cheap...(which i like ) and is readily available ...this ( i think ..) is a bit like Tim L previously suggested...
i,m still playing about with this ....

just a thought
niall

niall,

I like that. Simple & cheap (2 of my favorite). Here in Virginia we have 2 or so hurricanes in the fall. No massive earth destructing winds but I wouldn't want the turbine running then.

Appreciate the pix

hi Andy ..
erm .... two hurricanes .....i have absolutely no Idea what that must be like...5 centermiters of snow here
and some frosts has the whole west of the country is at a standstill.........and were getting off
easy compered to others

regards
niall

hi Andy ..
erm .... two hurricanes .....i have absolutely no Idea what that must be like...5 centermiters of snow here
and some frosts has the whole west of the country is at a standstill.........and were getting off
easy compered to others

regards
niall

All things considered it sounds worse than it really is. (if you ask the locals they over dramatize things) I'm from New York City.
These people close up EVERYTHING when 1 centimeter of snow lands.
It's mostly a lot of rain an high winds some flooding (but no flooding in my area). I have heard that there have been times when power was off for days. I made sure to install a whole house petrol generator and keep 25 liters on hand at all times.
I'm lucky it's no where near what Hurricane Katrina did to New Orleans or Andrew did to Miami but inconvenient enough.
I just wouldn't want a turbine going in that weather. <lol>

It is best to short before the diodes.
It avoids the surge currents in the diodes, though there are surge currents in other areas.
It also requires all 3 wires be dropped down to the tower base to the switch.
G-