Hi All, another technique is using a resistor in series with the primary to
drop the voltage enough to prevent the transformer heating during standby.
A relay would be required to short the resistor during transmit periods.
The resulting standby plate voltage would be in the ballpark of the operate
plate voltage. This would eliminate a surge in the primary circuit when
switching to transmit.
It also seems plausible to use the primary turn on surge limiter for this.
The relay normally used to short the limiter resistor would be energized by
the ptt circuit.
I have used the technique to keep twt voltages from soaring during standby
and it works quite well.
73,
Gerald K5GW
In a message dated 11/18/2012 7:52:52 A.M. Central Standard Time,
gzook@yahoo.com writes:
Would it not be possible to use a relay in the primary to disconnect the
transformer during standby? Of course, the contacts on the relay would have
to be able to "handle" the current. This should keep down the heating
factor.
Glen, K9STH
Website: http://k9sth.com
________________________________
From: Angel Vilaseca <avilaseca@bluewin.ch>
To: amps@contesting.com
Sent: Thursday, November 15, 2012 11:16 PM
Subject: Re: [Amps] Microwave Oven Power Transformer
For cost reasons, Microwave oven xformers are optimized specifically for
their use in a microwave oven.
They are OK as long as they supply their nominal power to a load.
In the standby mode, they get *very* hot.
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