[time-nuts] No more 60Hz! TEC Elimination
xformer at citynet.net
Mon Jun 27 23:07:37 UTC 2011
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
*********** 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 caf at omen.com 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
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