[Amps] SHV Connectors and B-

Paul Christensen w9ac at arrl.net
Thu Mar 13 11:06:59 EDT 2014


This morning I wrote:

"A female chassis connector would be installed on the PS, and a
recessed male chassis connector placed on the RF deck.  With 8-pins, I can
double-up on 240V and ground wiring."

Just the opposite: 240VAC power to the PS cabinet is sourced from the RF 
deck.  That means the PS cabinet gets a chassis-mounted, recessed male 
connector.

Some folks may wonder why I'll route AC power this way instead of connecting 
AC first to the PS cabinet.  The Alpha 77D chassis already has the 
step-start and AC input circuitry.  I see no need to move that over into the 
PS cabinet.  In essence, the 240V AC input power for the HV transformer 
loops out of the RF deck and into the PS cabinet.  HV DC is created by the 
transformer secondary, diode stack and oil cap. The resulting B+ and B- gets 
routed back into the RF deck by means of the SHV (B+) and Cinch connector 
(B-).

I suppose a dual breaker could be added to the new PS cabinet for the new 
Dahl HV transformer primary but that's already protected by the existing 
fuse pair in the RF deck.  Speaking of the panel fuses, Dick Byrd, N4UQ, 
sells a "big fuse" upgrade for the big Alpha amps.  Despite my best research 
effort, I have not found those fuse-holders in the major industrial on-line 
vendor catalogs.  I see a Bussmann and Littelfuse line that jumps into some 
big $$$ but that doesn’t seem right.  Before I bug N4UQ, anyone know that 
fuse-holder type?

Paul, W9AC 



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