[AMRadio] Transformer help

[Donald Chester]

>
>Yes I understand about critical inductance. A minimum load needs to be
>maintained depending on the inductance value of the swinging choke.
>
>I have read what I could find in the handbooks on the subject. What seems 
>to be
>missing is the information on dynamic regulation.
>
>73
>Gary  K4FMX

You are right.  There was an excellent article in GE ham news back in the 
60's.  I'll try to d ig it out.

With a load of about 500 mills at 2000-2500 volts and using a 8-30 hy 
swinging choke, it takes at least 25 mfd of filtering to tame the dynamic 
regulation in mine.  But beyond 30 mfd, I start blowing fuses when I key the 
transmitter.  I have another one with 1350 volts output and maximum  750  
mills, I use a 53 mfd oil cap with no problems, and the dynamic regulation 
is substantially better.

There is a time constant factor with the choke and output cap.  If they 
resonate at a syllabic rate or at your cw keying rate, the dynamic 
regulation will be horrible.  You need to get the resonant freq well below 
the syllabic or keying rate.

73 Don


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