Author Topic: Wind turbine brake switch  (Read 5415 times)

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Fused

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Wind turbine brake switch
« on: June 20, 2017, 01:28:24 PM »
Could this be used for a wind turbine brake switch?
Thanks all
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

kitestrings

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Re: Wind turbine brake switch
« Reply #1 on: June 20, 2017, 08:06:41 PM »
Seems overkill.  You can do it with a simple DPDT switch.
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kitestrings

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Re: Wind turbine brake switch
« Reply #2 on: June 20, 2017, 08:11:29 PM »
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Fused

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Re: Wind turbine brake switch
« Reply #3 on: June 20, 2017, 08:27:09 PM »
That switch I can get for $10 or less.
Over kill is good.
If I have my way,, I will be setting more small wind generators using the same circuit.
Doug
« Last Edit: June 20, 2017, 08:33:36 PM by Fused »
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

kitestrings

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Re: Wind turbine brake switch
« Reply #4 on: June 20, 2017, 08:35:56 PM »
Oh, maybe not then.  I assumed they'd be expensive.  My point is that you don't need 3-poles.

I can't seem to post images from this PC (damn Wins10).  It's me, but I could have done it three times on my old one.  Urh.

Maybe this way:

http://www.fieldlines.com/index.php/topic,148058.msg1027932.html#msg1027932

Fused

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Re: Wind turbine brake switch
« Reply #5 on: June 21, 2017, 09:27:01 AM »
If I had the a/c motor run switches laying around it would be different.
When it comes to purchasing the switch you mention
they are high dollar. So beings I can buy a drum switch
cheap why could I just not use 2 of the 3 poles?

I know it is just shorting out my positive and negative wire from
wind generator, but I cant make sense of how to wire it to the drum switch.

This switch is more for making my system more user friendly for my wife.
If I go to hospital, jail or otherwise, she can turn off power
from solar panels and hopefully use this switch to lock down any
small mills I have up.
So overkill on specs of the switch is the more the better.

thanks for your help.
Doug 
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

klsmurf

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Re: Wind turbine brake switch
« Reply #6 on: June 21, 2017, 10:33:58 AM »
Quote
I know it is just shorting out my positive and negative wire from
wind generator, but I cant make sense of how to wire it to the drum switch.

I was always told that shorting out a DC motor is a no no.  Shorting out 2 or 3 phases of a 3 phase alternator is fine.

Kevin
" A man's got to know his limitations " ------ Harry Callahan

Fused

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Re: Wind turbine brake switch
« Reply #7 on: June 21, 2017, 10:42:13 AM »
No power connects to the shorted + and - of the generator,

This is for PMA and a axial flux machines
I believe the 24v power is disconnected, then the generator gets shorted.
Maybe Im confused.
thanks
Doug
« Last Edit: June 21, 2017, 10:51:07 AM by Fused »
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

kitestrings

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Re: Wind turbine brake switch
« Reply #8 on: June 21, 2017, 12:23:50 PM »
I assumed you were talking about an axial-flux alternator.  If so, you short the AC windings and a regular 20A 2-pole, double-pole switch (DPST) will work just fine.  You do not disconnect the DC side.

If you are talking about a DC generator/motor Kevin is correct.

kitestrings

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Re: Wind turbine brake switch
« Reply #9 on: June 21, 2017, 12:38:24 PM »
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kitestrings

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Re: Wind turbine brake switch
« Reply #10 on: June 21, 2017, 12:40:18 PM »
one more try
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kitestrings

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Re: Wind turbine brake switch
« Reply #11 on: June 21, 2017, 12:48:52 PM »
photos not cooperating for some reason
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Fused

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Re: Wind turbine brake switch
« Reply #12 on: June 21, 2017, 01:39:51 PM »
I thought shorting only the mill d/c was common practice.
That is why I ran a 125 foot run and bringing the d/c into
my control room, would allow it to be used to brake the wing gen
from inside my house
I guess it will allow me to watch max amps through
my turnigy 130A meter.
So to hell with braking it/them then.

Wide open or nothing.
 ;D

Doug
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

SparWeb

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Re: Wind turbine brake switch
« Reply #13 on: June 21, 2017, 10:13:52 PM »
Fused,
Nothing wrong with shorting the AC side of an axial-flux gen.
Lots of things wrong with shorting the DC side (as you've already guessed).

I have my WT shorted right now.  Wind is stupid and gusty tonight, and I want to sleep tonight so I put the WT to sleep first.

The switch and wiring you sketched out in your first post would do nothing.  Worse, it has a middle position that allows open-circuit totally free turning!
Don't break the lines going from alternator AC to the rectifiers. 
Instead, add separate wires to the 3 rectifier AC terminals and put them on one side of the shorting switch. 
On the other side of the shorting switch, connect all 3 terminals in a short-circuit.
If the shorting switch is in the open (middle) position then it doesn't affect the system in any way at all.
When the shorting switch is in either the left or right position, then the 3 AC phases will be shorted, and the mill will stop.
This will not affect the DC because the short-circuit is on the opposite side of the rectifiers.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

SparWeb

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Re: Wind turbine brake switch
« Reply #14 on: June 21, 2017, 10:20:50 PM »
Like this:



PS this is clearly a 3-phase motor reversing switch.  Probably good for 25 amps or more.  Good switch for this application, and NO it won't make your turbine turn backward!!!
:)
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

Adriaan Kragten

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Re: Wind turbine brake switch
« Reply #15 on: June 22, 2017, 01:05:15 AM »
The maximum breaking torque of a PM-generator depends on how the generator is rectified. It is about 25 % higher for rectification in delta than for rectification in star (see KD 78 figure 4). This is because higher harmonic currents can circulate in the winding for rectification in delta. If the winding is rectified in star and if the star point is short-circuited too, you get the same high maximum short-circuit torque as for rectification in delta. However, this requires an extra cable from the star point to the short-circuit switch and now a 3-pole switch is needed. Short-circuiting of the star point is only possible if the star point is guided to the terminal block of the generator.

The short-circuit switch must be as close as possible to the generator and if you don't want to climb the tower, this position is the tower base. The large short-circuit current gives a certain voltage drop over the cables and this voltage drop makes that the peak torque shifts to higher rotational speeds as the voltage drop is larger. So the cables in between the generator and the short-circuit switch must be as short as possible and must have a sufficient large copper area.

midwoud1

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Re: Wind turbine brake switch
« Reply #16 on: June 22, 2017, 02:35:02 AM »
Breakswitch  with  dpdt . Like Kitestrings said not to much overkill


kitestrings

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Re: Wind turbine brake switch
« Reply #17 on: June 22, 2017, 06:00:58 AM »
Like to try again:
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OperaHouse

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Re: Wind turbine brake switch
« Reply #18 on: June 22, 2017, 06:05:47 AM »
If the rectifiers are up at the mill, you may have to short out the DC side.

Connect the mill +DC to  center left contact and battery to center right contact to battery.  Connect right lower contact to minus.   Then you have left normal, center open, and right shorted.

kitestrings

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Re: Wind turbine brake switch
« Reply #19 on: June 22, 2017, 06:32:37 AM »
Huh?  If the rectifiers are in the machine, and DC coming down the tower, I don't think you want to short there.

Fused

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Re: Wind turbine brake switch
« Reply #20 on: June 22, 2017, 09:00:30 AM »
yes, rectifiers are mounted on frame of axial.
Why can I not brake generator with DC?

when I take positive and negative in control room
from generator and touch them together the generator rotation
stops instantly.

That is where Im confused here.

Doug
« Last Edit: June 22, 2017, 09:26:34 AM by Fused »
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

kitestrings

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Fused

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Re: Wind turbine brake switch
« Reply #22 on: June 22, 2017, 09:50:37 AM »
quote
If the rectifier is up the tower and you bring dc down then things are a bit awkward as you can't short the dc side without isolating the battery.

But I can isolate the battery.

Doug
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

kitestrings

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Re: Wind turbine brake switch
« Reply #23 on: June 22, 2017, 09:57:26 AM »
Sorry Doug, I couldn't complete that train of thought - so, others may disagree, but there are several reasons why I would avoid this way:

To short the DC, you have to somehow disconnect, or block the battery, otherwise your shorting not just the turbine but also the battery.  This needs to happen reliably every time or you could have an unloaded turbine, or smoke where it doesn't belong.

I'd also be concerned that you might damage the rectifier.  Although I can't speak to this from experience, there location in this case is such that I wouldn't want to take the chance.

Generally switching DC is more problematic, particularly the "opening" piece if there are high wind shutdowns involved.  If it is just a parking brake, this may not be a concern.

~ks

Fused

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Re: Wind turbine brake switch
« Reply #24 on: June 22, 2017, 10:12:50 AM »
This will only be a parking brake.
Not to be braked when mill running.
I have to do no more than pull spade terminal
of positive from mill to a spade grounding block.
That separates the battery, and shorted the mill.


Thanks
Doug
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

Fused

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Re: Wind turbine brake switch
« Reply #25 on: June 22, 2017, 10:29:45 AM »
For my 3 phases on the axial flux, I use 3- 35a bridges using both a/c terminals.
6 coils 2 coils per phase, ends brought to brass connectors and screws on stator.
1 bridge per phase, Start of coils and end of coils to 1 bridge.

When I feel up to it I plan on rewireing my stator back to star.
Doug

« Last Edit: June 22, 2017, 10:59:02 AM by Fused »
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.

Fused

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Re: Wind turbine brake switch
« Reply #26 on: June 22, 2017, 11:13:43 AM »
"Connect the mill +DC to  center left contact and battery to center right contact to battery.  Connect right lower contact to minus.   Then you have left normal, center open, and right shorted."

Thanks OperaHouse, one question.
Lower right connects to mill negative?

Sorry for all the posts people.
Im not talented to get all my thoughts together in one post.

Thanks all
Doug
System specs: 480 watts peak solar, 8- 6v duracell batteries at 24v controlled with tristar 45,, wind generator is axial flux
with 5 foot blades

if good guys don't carry guns, only the bad guys will.