Sorry, out of my league. Sounds like you need someone with the Canadian or European calculations.
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| An Odd Ball https://brainfiller.com/arcflashforum/viewtopic.php?f=23&t=654 |
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| Author: | JPJ [ Mon Sep 14, 2009 4:21 am ] |
| Post subject: | An Odd Ball |
Is there anyone here who can help me please, i have a need to try an calculate the AC single phase Arc energy (230v - 20amps upto 470Amps at 50Hz) I then need to replicate this "Arc energy" at DC at 220volts Its a totally different application from switchgear and i know most of you would say its to low however i need to try and model this thanks Jas |
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| Author: | THE CABLE GUY [ Mon Sep 14, 2009 12:12 pm ] |
| Post subject: | |
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Sorry, out of my league. Sounds like you need someone with the Canadian or European calculations. |
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| Author: | JPJ [ Tue Sep 15, 2009 5:35 am ] |
| Post subject: | |
Thanks anyway Martin. i was wondering if i just used VA's, weather or not this would be representative in getting the idea across that an DC Arc is worse than an AC one. say for instance we pick up load at 230v 420A 50Hz rms (ignoring vectors fro the time being) That would be 96.6KVA however if the Arc lasted for 1.5s then 1/50 x1.5 = 0.03. therefore 96600 x 0.03 = 2.9KVA for the duration of the Arc. If i did the same test on DC (as the AC is rms so should be equivalent to DC) 230V x 420A = 96.6KVA However with the Arc lasting a 1.5s this equates to 144.9KVA for the duration of the Arc. so to get similar values at DC as those in AC
2900VA / 1.5 = 1933.3 / 420A = 4.6volts or / 230v = 8.4Amps so i think i need a different approach
( this is assuming that the distance and time it take to close the arc is constant) |
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| Author: | Vincent B. [ Tue Sep 15, 2009 2:32 pm ] |
| Post subject: | |
JPJ wrote: That would be 96.6KVA however if the Arc lasted for 1.5s then 1/50 x1.5 = 0.03.
therefore 96600 x 0.03 = 2.9KVA for the duration of the Arc. Why 1/50 x 1.5? That's only 1.5 cycle, quite far from the original 1.5 second... |
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| Author: | JPJ [ Tue Sep 15, 2009 8:55 pm ] |
| Post subject: | |
Ah! its always better to read a post first
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