KVar Calculations

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hitech67 Participant Join Date: Nov 2009 Posts: 3	KVar Calculations 06/29/2010 10:54 PM
	Dear Sir, We have following load in our factory. 150HP Crusher motor --- o1 no. 40 HP Crusher motor --- 02 nos. 10 HP electric motor --- 06 nos. 7.5 HP electric motor --- 02 nos. Total load connected = 305HP Present PF = 0.46 Please suggest me the Kvar value to improve PF upto 0.99 Regards, Sanjay
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msamad Guru Join Date: Feb 2009 Location: Houston, USA Posts: 946 Good Answers: 244	#1 Re: KVar calculations 06/29/2010 11:32 PM
	Refer to the generic calculation (reply # 5) from the earlier thread http://cr4.globalspec.com/thread/54230 You should be able to calculate your particular case from there. - MS __________________ "All my technical advices in this forum must be consulted with and approved by a local registered professional engineer before implementation" - Mohammed Samad (Linkedin Profile: http://www.linkedin.com/in/msamad)
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Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#2 Re: KVar calculations 06/30/2010 12:04 AM
	A fully loaded motor tends to have a high PF, whereas a lightly loaded motor tends to have a low PF. Your dominant crusher motors will have wildly varying loads, and hence highly fluctuating PF. The average PF might be 0.46, but if you try to correct it to 0.99, you are likely to overshoot sometimes into leading PF. This may incur some instability. Neither individual capacitors for each motor nor a conventional switching capacitor bank is likely to handle this well. However, I think it is CR4 member "marcot" who knows of a kind of fast-response capacitor scheme that could manage this. Be alert for this source of advice. __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
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mountk2 Power-User Join Date: Jun 2010 Posts: 348 Good Answers: 10	#3 Re: KVar calculations 06/30/2010 12:56 AM
	Total capacity 425 kvar with a 12 stage automatic relay. __________________ Knowledge sharing is a WIN-WIN situation
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Hameedullah Ekhlas Power-User Join Date: Feb 2010 Posts: 187 Good Answers: 11	#4 Re: KVar calculations 06/30/2010 2:00 AM
	See here it might help you, http://ecmweb.com/power_quality/pf-correction-single-induction-motors-20090601/
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