Slip Ring & Brushes with high temperatures

3 comments

Rate

menepoka Participant Join Date: Jun 2008 Posts: 1	Slip Ring & Brushes with high temperatures 06/30/2008 1:39 AM
	One of our slip rong 3-phase motor is recording high temperatures at the brushes & slip ring of red phase. Also the brushes are wearing out at a faster rate than usual. Can you give me possible causes for this?
	Register to Reply
	Pathfinder Tags: brush motor Slip Ring

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".

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	#1 Re: Slip Ring & Brushes with high temperatures 06/30/2008 7:57 AM
	A shorted winding on the red phase might account for it. Is the red phase brush sparking more than the others? Weak brush spring pressure might be another reason, though it sometimes occurs as a symptom, instead of a cause. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
	Register to Reply

ray.l Active Contributor Join Date: Jun 2008 Posts: 11 Good Answers: 1	#2 Re: Slip Ring & Brushes with high temperatures 07/01/2008 5:36 AM
	There are several possibilities for this occuring with most being easy to eliminate. Brush spring tension is easily measured with scales. Shorted windings are easily measured with a multimeter as well as insulation breakdown being checked with a megger. Control gear should also be checked this includes the main contactar at the MCC. I would suggest a low OHM meter. Excentricity (slip ring roundness) should also be checked as this could lead to "brush bounce". Are there shorting resistors in the circuit? If so then these should also be checked using a low OHM meter or a multimeter depending on the resistance.
	Register to Reply Good Answer (Score 2)

Morgan 23 Power-User Join Date: Mar 2008 Location: USA Soviet Socialist Dictatorship of Cook County& Illinois Posts: 207 Good Answers: 15	#3 Re: Slip Ring & Brushes with high temperatures 07/01/2008 7:12 AM
	After you check the possible electrical and mechanical causes outlined by others. Is the atmosphere in which the motor runs argon or nitrogen by any chance or is the motor at a high altitude or in an extremely dry area? Rarefied or inert atmospheres cause rapid brush wear. I am told that the graphite in the brushes are lubricated by the moisture ( humidity) in the air. If this is a possibiility, the solution imay be what is referred to as high altitude brushes. These were developed for use in aircraft.
	Register to Reply

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

Copy to Clipboard

Morgan 23 (1); PWSlack (1); ray.l (1)

You might be interested in: Slip Rings, Metal Ring Seals

	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 (81 right now) Show Members