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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WB4YVO on March 02, 2019, 04:11:58 PM

Title: Drake L7 Power Supply
Post by: WB4YVO on March 02, 2019, 04:11:58 PM
All, I need to increase this supply to 3KV at 1 Amp.  Can it be done..


Title: Re: Drake L7 Power Supply
Post by: W1ITT on March 02, 2019, 04:43:15 PM
A number of amateurs have built external supplies for the L7, and Peter W Dahl company used to supply an external plate transformer for it that goosed voltage and current available.  As I recall, the windings in the stock transformer use up all the space within the cores, so even the crazy option of rewinding it wouldn't work.
I say "crazy" because I'm in the learning curve of winding, from scratch, a plate transformer on C-cores.  It's good fun.  Look up KF8OD's web page for more inspiration.  But, to answer your question, if you want better plate voltage, build a supply and design to suit your own requirement.

Title: Re: Drake L7 Power Supply
Post by: w9jsw on March 04, 2019, 07:36:00 AM
I have an L4B that came without a PS. I am building a Plate modulated 813 rig and am building the PS in a compatible way so I can also use it on the L4B.

See the attached schematic. Note that it is not complete as I am changing the mains switch to a latching starter relay. My iron came from a Gates BC-1T. 2500V at 1.5A.

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