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Unread 09-03-2011, 06:41
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Mike Betts Mike Betts is offline
Electrical Engineer
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Team Role: Engineer
 
Join Date: Dec 2001
Rookie Year: 1995
Location: Homosassa, FL
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Re: Banebots RS-775 Case Short

Quote:
Originally Posted by Jack Jones View Post
IDK - Why test? They don't care what they sell us. I ordered two for spares and specifically asked for two that tested infinite resistance between leads and case. They sent two that tested 56k and 32k.

I will NEVER do business with them again!!
Jack, et al,

There is not a motor in the world which will pass that criteria.

Most of us spec out motors to a specific criteria form a recognized approval agengy (such as UL) called a Dielectric Withstand Test. The parameters for such a test would be that the device withstand a voltage (such as 2 times the rated maximum voltage plus 1000V) with less than a specified current (such as 1 mA) for a specified time (such as at least 60 seconds).

But we aren't buying UL listed motors, are we? We are using motors that are factory seconds or discontinued items that have been donated (or sold at a deep discount) to FIRST.

I'm not defending Banebots. This case shorting issue is not acceptable. However, you get what you pay for.

BTW, please check with your electrical lead mentor before attempting a DWT as you need specific test equipment and the test degrades the insulation being tested.

JMHO,

Mike
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Mike Betts

Alumnus, Team 3518, Panthrobots, 2011
Alumnus, Team 177, Bobcat Robotics, 1995 - 2010
LRI, Connecticut Regional, 2007-2010
LRI, WPI Regional, 2009 - 2010
RI, South Florida Regional, 2012 - 2013

As easy as 355/113...