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Unread 05-15-2017, 08:42 AM
Unsung FIRST Hero
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
Posts: 10,975
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Re: 775 Pro active cooling

I have a few observations to add here...
1. Many teams will block the vents in the output shaft end of the motor where cooling air is intended to enter to cool the armature.
2. Much of the heat that is generated at the brush end is due in part to current losses but brush friction and commutator arcing contribute to significant temperature rise.
3. Of the motors I have opened, electrical failure has resulted from a breakdown of the motor wire insulation breakdown. At higher temperatures, the insulation will become plastic and the sharp edges of the armature will be forced through the insulation and short to the armature laminations. It seems that this motor could benefit from additional insulation on the armature structure.
4. High temps at the fan will cause the fan to disengage with the armature resulting in a failure to move cooling air through the motor.
Many of the issues with this motor are the same we experienced with the fisher Price motors.
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Good Luck All. Learn something new, everyday!
Al
WB9UVJ
www.wildstang.org
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Generating steam since 1996.

Last edited by Al Skierkiewicz : 05-20-2017 at 02:16 PM.
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