Energy Saving

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The Microman Member Join Date: Sep 2008 Posts: 8	Energy Saving 09/03/2008 9:10 PM
	Has anyone found a good way to save on a motor or compressor? I have read all the different comments on power factor and how it effects a motor or compressor.if the motor or compressor has a PF of 0.75. What I am thinking of is if a motor or compressor draw 120 volt at 5.6 amps what can be done to make it more effecient ? The Microman
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	Pathfinder Tags: cut energy cost design effecientcy Energy saving

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Sparkstation Guru Join Date: Nov 2007 Location: Christchurch, (The Garden City), South Island, New Zealand Posts: 4395 Good Answers: 230	#1 Re: Energy saving 09/03/2008 9:16 PM
	Hello The Microman You can not get the motor up to unity Power Factor = 1. The cost of improving the PF past 0.85 would be considerable. The exercise of improving the PF on your small motor from 0.75 to 0.85 is not really worth the bother. If you had 5kW or more of motors, then it does become cost-effective to improve the PF. The larger the motor installation, the more cost-effective PF correction becomes. Kind Regards.... __________________ "The number of inventions increases faster than the need for them at the time" - SparkY
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JRaef Guru Join Date: Sep 2006 Location: California, USA, where the Godless live next door to God. Posts: 4665 Good Answers: 804	#2 Re: Energy saving 09/03/2008 11:02 PM
	But improving the power factor does not really save energy. And adding capacitors to single phase motor circuits is tricky at best. Interactions with starting caps can be disastrous. It's difficult to improve the efficiency of a single phase compressor. It is a cyclical load which needs a lot of brief moments of high starting torque, so VFDs are not very applicable. Then you have the fact that single phase motors are motoriously inefficient compared to 3 phase motors. the most demonstrably effective way to save energy on compressed air systems is to improve the air delivery system. Fix leaks, avoid pressure drops, keep the air dry and clean. __________________ All I every really wanted to be, was... A LUMBERJACK!.
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user-deleted-1105 Guru Join Date: May 2007 Location: Harlow England Posts: 16512 Good Answers: 670	#3 Re: Energy saving 09/04/2008 3:05 AM
	Turn 'em off more often? Del __________________ health warning: These posts may contain traces of nut.
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Anonymous Poster	#4 Re: Energy Saving 09/05/2008 2:34 AM
	Capacitor bank of appropriate rating connected in parallel at the motor terminal may improve power factor upto 0.95 and this arrangement will save energy, i think.
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JRaef Guru Join Date: Sep 2006 Location: California, USA, where the Godless live next door to God. Posts: 4665 Good Answers: 804	#6 In reply to #4 Re: Energy Saving 09/05/2008 2:53 PM
	No, it will not save any appreciable amount of energy. This is a common myth put forth by people who push capacitors. Improving the power factor has benefits, but not energy savings. And besides, single phase motors already have capacitors, so adding them in can create resonance issues that can destroy the motor, caps or other nearby equipment. __________________ All I every really wanted to be, was... A LUMBERJACK!.
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Scapolie Guru Join Date: Jan 2007 Posts: 1058 Good Answers: 8	#5 Re: Energy Saving 09/05/2008 4:33 AM
	This is easy, stop using the compressor! Spencer.
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Goodho Commentator Join Date: Jun 2008 Posts: 80 Good Answers: 5	#7 Re: Energy Saving 09/08/2008 7:19 PM
	Microman, Do you get charged by the kilo-watt or do you pay a penalty to the utility because of the power factor that you have already? In the U.S. we can only be charged for real power, unless we are so inductively loaded that the power factor is below about 0.7. Then the utility can charge a penalty. Adjusting PF might be nice for the utility, don't expect to see any significant savings on your electric bill from a PF adjustment on a 1/3 to 1/4 horsepower motor. Try 3 phase to be more efficient
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Anonymous Poster (1); Goodho (1); JRaef (2); Scapolie (1); Sparkstation (1); user-deleted-1105 (1)

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