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Vfd's


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#1 emike

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Posted 17 November 2006 - 02:34 AM

i AM TRYING TO FIGURE OUT HOW TO CALCULATE FOR A MAIN DISCONNECT FOR A CONTROL PANEL. THE PANEL CONSISTS OF A VARIETY OF VFD'S RANGING FROM 1 HP TO 15 HP @ 480 VOLT. CAN ANYONE HELP ME OUT? THANKS

#2 jraef

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Posted 17 November 2006 - 09:42 PM

Read the Max. Amps on the nameplates of all the VFDs, add them together, mutiply the sum by 1.25 and pick the next size main breaker available.
"He's not dead, he's just pinin' for the fjords!"

#3 jOmega

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Posted 20 November 2006 - 01:13 PM

Following JRAEF's advice, it is important to remember that when adding up the currents of all the VFD's ....
that you use the listing for the INPUT AMPS and not the output amps.

They will be different numbers because of the POWER FACTOR of each VFD.






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