> I am still working on the 4-1000A amplifier design and have decided to
> separate the PS from the RF chassis. I still don't have my HV
> transformer but I am thinking that it will be too big to get into my
> presently designed cabinet of 14" x 14" x 12" dimensions along with the
> 4-1000A and all the plate tuning circuitry and filiment transformer.
>
> I will be putting the power supply under the bench in a built in (wood)
> cabinet that is already there. The PS chassis/cabinet itself will be
> made of aluminum but it will set on a shelf inside a closed door so I am
> wondering about wheather I will have to wory about heat build up? It
> will be solid state diodes, capacitors and transformer. Do I need to put
> in a fan in the side of the cabinet?
>
>
> ::You undoubtedly will, unless the cabinet's in a very cool
> air-conditioned room at all times. You left out "bleeder resistors" from
> your parts list (above), and that's where most of the heat actually comes
> from. For a 4kV power supply to bleed down to <40V inside of 10-15
> seconds (my normal criteria for discharging HV power supplies), your
> bleeders will be dissipating over 100W. My own 4-1000A HV PS uses 80K of
> total bleeder resistance and dissipates 200W. Without a cooling fan in
> the PSU, those resistors would likely burn up or unsolder themselves.....
> -WB2WIK/6
>
>
> The second item I am asking for design help on is the power cable to the
> RF chassis. This will run about 6 feet from the under desk cabinet to
> the top of the desk through a hole in the bench. It will be near my
> knees so I dont want it to arc (5 Kv) to any part of my body.....#8-)
> What should I use for transmission cable? What is a source for such
> cable?
>
> :: I use 20kV test prod cable, #18ga stranded conductor with silicone
> rubber insulation, readily available from many sources. Mine is made by
> Gore, but lots of people make this stuff. I use multiple, separate return
> and ground cables, but many feel more secure if the HV lead itself is
> shielded (not a bad idea), so you can slip the braid from some RG58 or
> RG59 cable over the HV test prod cable and use shielded, grounding
> connectors on each end if it makes you feel better. (Frankly, it doesn't
> make me feel any better, at all, and I use ordinary 7kV Millen HV
> connectors with separate ground cabling.) -WB2WIK/6
>
>
>
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