3 Phase Motor Rotates

7 comments

Rate

harjeetsinghengg Commentator Join Date: Jul 2008 Posts: 56 Good Answers: 1	3 Phase Motor Rotates 06/21/2012 2:46 AM
	How it is possible that same 3 phase motor rotates in different direction at different user end even though users are also follow R Y B phase sequence as followed by manufacture.
	Register to Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

These comments received enough positive votes to make them "good answers".

JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#1 Re: 3 phase motor rotates 06/21/2012 3:16 AM
	Because electrons don't know or care what colour the insulation of the wire is. Sometimes mistakes are made, and the phases do not correspond to the standard for R,Y,B. __________________ "Love justice, you who rule the world" - Dante Alighieri
	Register to Reply

harjeetsinghengg Commentator Join Date: Jul 2008 Posts: 56 Good Answers: 1	#2 Re: 3 phase motor rotates 06/21/2012 3:35 AM
	Right JohnDG It means we can ensure the phase sequence but how one will ensure that R is R, Y is Y and B is B in 3 phase system.
	Register to Reply

JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#3 In reply to #2 Re: 3 phase motor rotates 06/21/2012 3:38 AM
	Get a phase sequence indicator. __________________ "Love justice, you who rule the world" - Dante Alighieri
	Register to Reply

harjeetsinghengg Commentator Join Date: Jul 2008 Posts: 56 Good Answers: 1	#4 Re: 3 phase motor rotates 06/21/2012 3:54 AM
	Please correct me If I m wrong. The phase sequence can only indicate the next phase is electrically 120 degree ahead or not.
	Register to Reply

JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#5 In reply to #4 Re: 3 phase motor rotates 06/21/2012 4:02 AM
	Correct. But as long as the sequence is the same, the motor will rotate in the same direction. There is no absolute "first phase" because the start time is arbitrary. Thus (R,Y,B) ≡ (B,R,Y) ≡ (Y,B,R) rotates one way, and (R,B,Y) ≡ (B,Y,R) ≡ (Y,R,B) rotates the other way. __________________ "Love justice, you who rule the world" - Dante Alighieri
	Register to Reply Good Answer (Score 4)

harjeetsinghengg Commentator Join Date: Jul 2008 Posts: 56 Good Answers: 1	#6 In reply to #5 Re: 3 phase motor rotates 06/21/2012 4:11 AM
	Thanks! JohnDG
	Register to Reply

silverfox Power-User Join Date: Nov 2011 Posts: 286 Good Answers: 15	#7 In reply to #5 Re: 3 phase motor rotates 06/22/2012 9:14 AM
	Colours please Timothy! Red Yellow Blue ZZZzz Right answer though. The German way was always interesting with the phase colours all being black and the neutral being blue. One of the few countries to benefit from screwing around with our good old phase colours.
	Register to Reply

These comments received enough positive votes to make them "good answers".

Copy to Clipboard

	Got Something to Say?
	Ask a Question Start a Discussion

	Aerospace
	BioMech & BioMed
	Chemical & Material Science
	Civil Engineering
	Communications & Electronics
	Education and Engineering Careers
	Electrical Engineering
	General Discussion
	Instrumentation
	Manufacturing
	Mechanical Engineering
	New Technologies & Research
	Software & Programming
	Sustainable Engineering
	Transportation

	Site Directories
	Forum Directory Blog Directory User Group Directory RSS Feeds CR4 Rules of Conduct CR4 FAQ Site Glossary Who's Online (94 right now) Show Members