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Unread 06-02-2004, 07:35
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Al Skierkiewicz Al Skierkiewicz is offline
Broadcast Eng/Chief Robot Inspector
AKA: Big Al WFFA 2005
FRC #0111 (WildStang)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1996
Location: Wheeling, IL
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Re: Do we need to use the gnd stud and MAXI fuse block

Quote:
Originally Posted by SuperDanman
The use of freeze-spray has been discussed several times before - it is generally agreed that pre-cooling before a match can give you better breaker performance. However, can freeze spray damage the breakers? If you freeze your hot breakers right after a match, will the rapid cooling affect their performance in the long run? How about for their duty-cycle - say three competitions?
It is my opinion that the freeze spray can do no more harm than the tripping of the breaker in the first place. At high currents and high temperatures, the contacts of the breaker have to be pitting when the circuit opens. There is a lot of current and a lot of inductance, potential power, etc., stored in the motors that would cause arcing when the breaker trips. Many teams have used freeze spray but it can only hold off the problem a few seconds. The breakers have no thermal mass so even if they are cold, they can't hold it.
As far as damage from direct application, there is no significant connection between the bimetal device and the case and they are sealed pretty well so there is no intrusion of the freeze spray in liquid. If the breakers are constantly cycling (a buzzing sound will be heard) then the overtemp of the metal parts will surely have some permanent effects.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Storming the Tower since 1996.