They are cheaply built with little insulation. A good power surge or lightning strike will puncture the insulation and the primary will arc to the frame/core on peaks of the wave.
Door bell transformer failure will have a marked 120 Hz rough note. The homeowner should consider themselves lucky if you find it for them as old transformers are often simply screwed to floor joists under the floor in the area of the front door. The arcing represents a fire hazard. Fortunately, more modern door bells, etc. eliminate the old transformers. 73, ... Joe, W4TV On 10/22/2010 10:49 PM, Jim Miller wrote: > What is there about a transformer that causes so much grief? Curious... > > 73 > > jim ab3cv > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html