ELCB

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loyd Associate Join Date: Mar 2011 Posts: 48	ELCB 04/05/2011 11:53 AM
	hi friends i just want to know how to connect ELCB for 3 phase motor? because here we get only 3 phase but no neutral.
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#1 Re: ELCB 04/05/2011 12:29 PM
	L1 L2 L3 ignore N __________________ The reports of my death are greatly exaggerated.
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loyd Associate Join Date: Mar 2011 Posts: 48	#2 In reply to #1 Re: ELCB 04/05/2011 1:01 PM
	only L1 L2 L3 In this condition as far i know the ELCB will not trip. i already tried this
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#3 In reply to #2 Re: ELCB 04/05/2011 1:25 PM
	It won't trip on the test button. That will be connected between one of the L terminals and N. If you want the test facility either run a neutral to one of the N connections or connect one N to earth. __________________ The reports of my death are greatly exaggerated.
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electricalexpert65 Guru Join Date: Oct 2009 Posts: 2061 Good Answers: 169	#4 In reply to #2 Re: ELCB 04/05/2011 10:13 PM
	Tony is right. I wonder why it should not work. During normal conditions, motor being a balanced load, currents in L1, L2 & L3 would be equal and hence there woud not be any residual current. When there is an earth leakage, this balance is affected and the ELCB must operate, if the leakage current is above the ELCB sensitivity level.
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Paulusgnome Power-User Join Date: Oct 2007 Location: Christchurch, New Zealand Posts: 328 Good Answers: 29	#5 Re: ELCB 04/06/2011 4:47 PM
	The other posters are correct to say that the ELCB should work fine with a 3-phase circuit that has no neutral, the line currents will sum to zero. As far as the test trip goes, I guess that different manufacturers do this differently. The 4-pole RCCBs that we use here (GE brand fwiw) have an internal resistor that the test trip connects between L2 (upstream) and L3 (downstream), so if the neutral is not being used, the test trip still works. This is marked on the little diagram that is printed on the case. __________________ paulusgnome
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loyd Associate Join Date: Mar 2011 Posts: 48	#6 In reply to #5 Re: ELCB 04/07/2011 9:28 AM
	is there any different types of RCD's available which we can use only for 3 phase without neutral?
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#7 In reply to #6 Re: ELCB 04/07/2011 1:16 PM
	All of them. It's just that the test button will not work without a neutral. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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