Fired up the HP 226519 50V 57Amp power supply for the first time. The connectors are Unobtainium, but I didn't want to damage them by soldering to the terminals. So I soldered to the AC inlet board for now.

• Take the cover off to expose the boards and wiring
• Remove the small AC input board with connector and filtering
• Solder 240 line cord to back of board, including green to middle
  
• Connect green wire to ground mounting hole with 6-32 screw and nut
• Tape the assembly for safety
• Sacrifice a floppy disk power connector per the k3hkr page
  

It might be possible to do this and reinstall the board.

On plugging it in, the fans run and the floppy disk switch works, the output shows 50.4V on my meter. The fans run 10-15 seconds after unplugging...fair amount of energy storage there.

The power supply consists of a AC line board and an output and control board. The power interface between them flows on three relative heavy wires. Putting the scope on those wires shows about 800V square wave at 100 kHz on each. This power apparently flows into some transformers on the output board that have the label "Hi-Pot".

The output board has "Astec" printed on it, lending some support to the idea that HP buys them from Astec. If so, the Larcan site has a manual.

I'm trying to understand the design for this supply to see if it's useful for other purposes. My thoughts so far...

• Input power factor correction generates a filtered 400V DC bus
• 100 KHz H-bridge inverter from 400VDC generates the 800V square wave
• Not clear why 3 wires at 100 kHz, 3 phase? But there's only two transformers
  
• The two stages have no line isolation, producing +/-120V AC offset
• 100 kHz feed two transformers on the output board, providing isolation (and lower voltage)

How to use this for other things...

• 5X Voltage multiplying from 800V square wave to run an 8877, GS-35B
• 400VDC at 7.5 amps for ???
• 3KW induction heater power supply
  

FreeCAD model of M2 Driven Element

Here's a FreeCAD model of M2 Driven Element. I don't know how to use the feature that creates 2D views of the part...FreeCAD is incomplete.

M2 Driven Element Design

M2 appears to have the right idea about driven element design. It's much more rugged than the K1FO driven element design. The standoffs get broken and flexing causes strains that break the fragile wire connecting to the UG-141 coax. The picture below comes from a Directive Systems product photo.


Here's a picture of an M2 Antenna Inc. two meter driven element phasing block.

The phasing line uses RG-6 and F connectors, which seems wrong to hams. But, modern F connectors come with multiple O rings for waterproofing and cheap tools for assembly. The RG6 doesn't limit power handling because most of the power couples to the phased element by radiation and conduction around the folded dipole. Also, the 70 ohm impedance doesn't matter because the line is 1/2 wave long.

The 1/4 inch elements feed into the block through 1/2 inch delrin rods about 5/8 inch long. The delrin rod is drilled for the elements. A set screw pinches the delrin and the element to hold it in place. It's not clear how the tolerances ensure that this part of the design remains waterproof.

M2 describes their driven element design well.

The heart of these antennas is a driven element module originally designed for maritime ATS satellite service. All connectors are O-ring sealed to the CNC machined block. Internal connections are sealed with a space-age silicone gel with nearly 4 times the dielectric strength of air. The balun connectors are triple sealed on the coax and nut-sealed at the block connectors.

A closeup of the connections in the hole show an 18 gauge wire pushed into the F connectors and a somewhat larger wire connected to the elements. It appears that the end of 1/4 inch elements gets drilled, a wire inserted and probably pinched.



The driven element block connects to the boom with a single screw and a curved cutout to align the assembly.

Why do I still have a web page?

The idea of putting a file up on a web page with FTP is sooo 2005. I should have moved over to a blog a long time ago. http://wa1hco.net is not long for this world.