On 12/16/2005, Scott Douglas wrote:
What makes a transformer hum? Hi Scott: It is my understanding that in conventional transformer designs with stacked laminations, the most common source of hum is vibration of the laminations against each other as they move with the changing flux field. A common treatment to reduce hum in such transformers is to vacuum impregnate the transformer with varnish or some similar material to restrict the relative movement of the laminations. You mention that your transformers have toroid cores, so this explanation may not apply to that construction. However, I suggest that you review the core construction and the overall transformer construction to look for places where the changing flux field could cause relative motion of the components. Most transformer manufacturers are quite familiar with the sources of hum and the various methods that can be used to mitigate it. Have you reviewed the problem with your transformer manufacturer? Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected] http://www.randolph-telecom.com <http://www.randolph-telecom.com/> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
