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Geoff Schultz
 
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"Doug Dotson" wrote in
:

James,

I appreciate your concerns but I think you have gotten some incorrect
information about the KISS. The KISS approach is to keep things
simple, maybe a bit too simple in some aspects. I'm currently working
on a controller that will solve some of the problems.

More comments below.

Doug
s/v Callista

"James" wrote in message
. ..
Thanks for teh reply Doug!

I have two concerns with the KISS Unit. I have been told that:

1) There is no slip ring, hence it can not rotate 360. You have to
watch to make sure it doesn't twist around and damage itself.


It is true that it does not have slip rings. This enhances
reliability. It is
not true that it cannot rotate through 360 degrees. It can rotate up
to 3 complete revolutions in either direction. The very heavy cable
just twists. A tortion spring limits the rotation to 3 turns. In the 3
years I have had mine it has never wound up more than 1 turn.

In other words, not for unattended operation.


Actually, the KISS is not intended for unattended operation even under
normal condition. There is no charge controller. Unattended operation
will lead to uvercharging and destroy you batteries or worse.

2) There are thermal breakers in it. When the wind really pipes up
and you shut down by shorting the unit as you are supposed to do, the
windings can get hot and pop the breakers.


I have never had this happen. When the unit is stopped by shorting the
windings, rotation is slowed almost to a stop. No chance to build up
much heat. I've had mine in up 50 mph winds and it spins at maybe 1/2
rps. I flipped to switch to stop it when winds were around 40 when the
thermal breakers started to activate. The mill came to a nice smooth
stop. I believe what you think are thermal breakers are actually
thermal switches that short that windings due to overspeed. They close
causing the mill to slow. I've have this happen several times. I can
not see any freewheeling possible except for in an actual failure
situation. But any mill has that possability.


My experience does not match Doug's. I've found that once a thermal
breaker opens that it's next to impossible to stop the unit. The other
2 thermal breakers should be at about the same temp and should be close
to opening. Shorting the remaining windings seems to produce more heat
than generating power does and this causes them to open too. Also, once
a thermal breaker opens this causes the blades to spin faster which
produces more power which creates more heat which causes the breakers to
open...

The only way that I've been able to shut it down is by doing so before
any of the thermal breakers open or by turning the generator 90 degrees
to the wind with a boat hook. I've had mixed results with that. See
http://www.geoffschultz.org/2004_Sai...S_Failure.html for
what happened one day when I tried this.

-- Geoff