At 12:02 1999-01-09 -0400, you wrote:
>        Hi !!!:
>
>
>        Some days ago you clear me the doubts about how to connect my
transformer
>with 115 or 220vac.  Ok, I learned the lesson.
>
>
>        I�m using it in my system (One pic, and four CI more).  I read the
current
>that flows out of my power (using the transformer) and it�s about 5mA but
>the transformer get pretty hot but It can give me 450mA.
>
>        I have used only One primary to 115vac and connected in series the
output
>to get the maximum voltage.
>
>        Is it normal that this device get so hot ????

Some small types are barely touchable although running at low load.
This is due to high internal losses, as 50/60Hz is designed for efficiency
in large trafos, generators and motors.

That is one reason switchmode powersupplies are so small and efficient,
working at 30+kHz.

Take care to let air flow to cool it.

 I have used a very small 50Hz 240VACprim 0.35VA trafo, and it is almost
the same temperature wether the outpot is open or shorted!

As I expected airflow in the design to be poor, I made a aluminium plate to
press on one side of it to cool it and spread the heat.

/Morgan
        Morgan Olsson                   ph  +46(0)414 70741
        MORGANS REGLERTEKNIK            fax +46(0)414 70331
        H�LLEK�S           (in A-Z letters: "HALLEKAS")
        SE-277 35 KIVIK, SWEDEN               mrt@iname.com
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