[Amps] Serious design stage

[rlm]

On Apr 20, 2004, at 11:29 AM, Jim Isbell wrote:

> After collecting parts for most of a year I am in the serious design=20=

> stage of a 4-1000A linear.  The power supply, because of its size is=20=

> to be external and connected by a cable.
>
> In the first design I was going to bring the 6500VDC power through a=20=

> cable to the linear.  But then it occurred to me that since the main=20=

> reason for the separate supply was the size...which is MOSTLY the=20
> 12KVA transformer I am using.  It might be safer to just make the=20
> transformer external and have the rectifiers and filter capacitors in=20=

> the transmitter case thus allowing the only the transmission of AC, at=20=

> a lower potential, (using a voltage doubler circuit) in the cable. =20
> Thus, by just turning off the input power I could eliminate the=20
> potential on the cable instantly...or almost so...while the filter=20
> capacitors which are the biggest danger would be in the transmitter=20
> cage and would be connected to shorting circuits controlled by the=20
> safety switches on the lid of the transmitter.
>
> There must be some reason this is not a good idea as I have never seen=20=

> it done.
>
> Any comments???

=F0  Jim -- I see it as a sound idea provided there is room for the=20
filter capacitors in the RF unit.  However, a 12kva transformer would=20
be more suitable for an 8171 than an 8166/4-1000A.  Switching to such=20
would not require a larger chassis since either tube requires c. 8" x=20
8" of chassis space.  Advantages with the 8171 are a simpler tuned=20
input circuit, a quieter blower, and 6x the peak emission.   If you=20
have a 4" deep chassis, Peter Dahl makes a 7.5v, 75A filament=20
transformer that will fit in a 4" chassis.   On E-bay, I've seen 8171s=20=

go for c. $300.

cheerz
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
Rich Measures, AG6K, 805.386.3734.  www.somis.org/