Chuck, It's according to who designed the transformer, and what iron, and wire they used. Some transformers can be ran up to 17 kilogauss (1.7 Tesla), but the magnetizing current really shoots up after 15 kg, and they can get hot. However, that's M-6 material, and I highly doubt they used that, as it is expensive. Most likely, for that, it was M-19, which is ran around 10-12 kg, but if it got that hot, it either didn't have enough iron in it, not enough turns in the primary, or it had an internal short, but it should have smoked at that.
The problem is, that a lot of manufacturers spec'd transformers to run right on the edge, and Heathkit was guilty of doing that somewhat. The only reason was the cost came down, and the size. They also used a different figure on sizing the wire, and run it at a higher current density than they should, sometimes around 400 circular mils per ampere. A basic rule of thumb, for a decent transformer, is at least 700-800 cir. mils per ampere, and continuous duty, 1000 or over. If you get a chance, try out a common door bell transformer, and test the temperature. They were meant for intermittent duty, and they used to run pretty hot. Best, Will *********** REPLY SEPARATOR *********** On 6/27/2011 at 3:38 PM Chuck Forsberg WA7KGX N2469R wrote: >I picked up an older stereo amp to use its parts for a project. >With no load at all, the power transformer runs uncomfortably hot. >At 50 Hz it might make a good space heater for a while. > >-- >Chuck Forsberg WA7KGX N2469R [email protected] www.omen.com >Developer of Industrial ZMODEM(Tm) for Embedded Applications > Omen Technology Inc "The High Reliability Software" >10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 > > >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET Smart Security, version of virus signature database 5851 (20110206) __________ > >The message was checked by ESET Smart Security. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
