ID Fans and Currents

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harshadbhale Participant Join Date: Mar 2009 Posts: 2	ID Fans and Currents 04/27/2009 3:22 PM
	why current of ID fan so vary in running condition ( varry between 50 to 200A, for 132 KW, 960 rpm & FL current of motor is 227A)
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Kilowatt0 Guru Join Date: Aug 2007 Location: Earth - I think. Posts: 2143 Good Answers: 165	#2 Re: ID Fans and Currents 04/27/2009 5:31 PM
	To guest: Yes ID fan=Induced Draft fan (at least everywhere I have worked). To OP: Since you don't mention a VFD, I have to guess (I hate guessing) that you have some sort of damper vanes. Two things to check: 1. Is there any slop in the mechanical linkage. 2. Check the PID loop that controls the dampers, if it is tuned too fast it can cause oscillation, which would show up as variable amp draw on the motor. If neither of those is the problem, then start looking at the feed/process that the ID fan is used for (Boiler, Furnace...). It could be under/over feeding sporadically. Good luck! __________________ TANSTAAFL (If you don't know what that means, Google it - yourself)
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Codemaster Guru Join Date: Jul 2005 Location: Stoke-on-Trent, UK Posts: 4496 Good Answers: 137	#7 In reply to #2 Re: ID Fans and Currents 04/28/2009 7:04 AM
	Steady on Kilowatt0 He didn't say it was a problem, maybe he's just asking out of curiosity. This sort of input power variation over fan duty range is not unusual. Power usually increases with reducing fan pressure and increasing flow). Cheers...........Codey __________________ Give masochists a fair crack of the whip
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jdretired Guru Join Date: May 2007 Location: Australia. Posts: 1642 Good Answers: 81	#3 Re: ID Fans and Currents 04/27/2009 11:10 PM
	Current varying over what period of time? motor oscillating or over a number of hours? Regards JD.
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AussieBob Power-User Join Date: Oct 2008 Location: Auckland, New Zealand Posts: 463 Good Answers: 43	#4 Re: ID Fans and Currents 04/27/2009 11:27 PM
	What type of fan is it? If more than one, how many fans interconnected? (I have witnessed a fan failure on a 500MW boiler where one fan was in a stall condition for several months in 3-fan-in-parallel configuration - and it wasn't a power saving exercise. It was a bit like the proverbial turbine blade through the roof event) Centrifugal with or without inlet guide vane control? Axial Flow with or without inlet guide vane control? Is fan operating duty variable using motor speed/ inlet guide vane/ outlet damper?
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B.JEYACHANDRAN Associate Join Date: Apr 2009 Location: Muscat Oman Posts: 27	#5 Re: ID Fans and Currents 04/28/2009 1:04 AM
	HI Friend, tell me you put What type moter that is saquiral cage or silpring motor becase slip ring moter always having small fluxvation due to not praperly geting the star point at rotor side check your damper possition may be damper fluxuate to maintane the furnace draft when we put the VFD for the pannel for the motor we may control the assilation by adjusting rampup and ramdawn time
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nesubra Guru Join Date: Nov 2006 Posts: 729 Good Answers: 2	#6 Re: ID Fans and Currents 04/28/2009 5:45 AM
	The fan load keeps varying depending upon the air requirements.Second Inertia of ID fan is high.heck the starting time at start on DOL.dampers are used to vary the speed of fan.Now a days VFD is used which results in energy saving when motor has to run at different speeds __________________ To avoid crticism do nothing,say nothing,be nothing
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Anonymous Poster (1); AussieBob (1); B.JEYACHANDRAN (1); Codemaster (1); jdretired (1); Kilowatt0 (1); nesubra (1)

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