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 Post subject: Motor Controls
PostPosted: Fri Feb 22, 2019 8:05 am 
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What electrode configuration would you use?


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 Post subject: Re: Motor Controls
PostPosted: Fri Feb 22, 2019 9:33 am 

Joined: Tue Dec 31, 2013 12:19 pm
Posts: 31
Fuse clips could be VCBB or HCB. At the breakers and motor starters it is VCBB. All else being equal, if you run the calc's on both VCBB and HCB, HCB will give you the higher incident energy. So I would use HCB.


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 Post subject: Re: Motor Controls
PostPosted: Mon Feb 25, 2019 5:01 am 
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vCBB unless the dimensions work out to shallow which this has to be close. Due to enclosure sjze VOA might be more appropriate though. When does CF reduce VCB 5o equal VOA?


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 Post subject: Re: Motor Controls
PostPosted: Tue Mar 05, 2019 10:00 am 
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Joined: Wed Jun 04, 2008 9:17 am
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Location: Spartanburg, South Carolina
I tried varying box sizes with the IEEE1584 Excel Calculator and found that with 480V, 20kA bolted fault, 1" gap, 24" working distance, 200 ms arc duration, VOA gives 2.15 cal/cm². Increasing box size from 20"x20" to 60" x 60" in 5" increments, results in IE reducing from 4.56 cal/cm² to 3.44 al/cm² at 50" x 50" and not reducing for larger sizes.

Most likely that interpolations too far beyond the tested sizes to not result in values approaching the open air case.


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 Post subject: Re: Motor Controls
PostPosted: Tue Mar 05, 2019 11:07 am 
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jghrist wrote:
I tried varying box sizes with the IEEE1584 Excel Calculator and found that with 480V, 20kA bolted fault, 1" gap, 24" working distance, 200 ms arc duration, VOA gives 2.15 cal/cm². Increasing box size from 20"x20" to 60" x 60" in 5" increments, results in IE reducing from 4.56 cal/cm² to 3.44 al/cm² at 50" x 50" and not reducing for larger sizes.

Most likely that interpolations too far beyond the tested sizes to not result in values approaching the open air case.


The adjustment stops at 1244 mm.


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 Post subject: Re: Motor Controls
PostPosted: Mon Apr 01, 2019 11:14 am 

Joined: Mon Nov 24, 2008 6:42 pm
Posts: 5
Location: Nashville, TN
Jim,
I mean no disrespect, but you are shown as Vice Chair of the IEEE 1584-2018 Committee.

Why are YOU asking us what electrode configuration this is? You should be telling us.

This is where I am frustrated w/ the new IEEE 1584-2018. You didn't make any effort to give us real-world examples of your laboratory test configurations. You should have provided a table showing all the common real-world examples of VCB, VCBB, HCB, etc. configurations.

How am I as an end-user supposed to know what your intentions were? You guys who developed this standard are the only people in the world that can answer YOUR question. All this standard did was create more CONFUSION.


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 Post subject: Re: Motor Controls
PostPosted: Fri Apr 05, 2019 3:48 am 

Joined: Mon Aug 04, 2014 5:19 pm
Posts: 13
Yes I second the motion. The latest IEEE 1584 created a "Tower of Babel" for the practicing engineer and it seems like everyone will have a different interpretation on the electrode configuration.
Jim


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