At 10:54 AM 2/18/2011, Bob Bruninga wrote:
Is there a Amsat BB favorite between switching and linear [power
supplies]?
I won't speak to noise, which is the only potential issue with switching power supplies, but other than that, I am writing an article for QST that points out how the world of power and emergency power has changed drastically over the last decades. Entirely due to switching power supplies and regulators:
PROS:
- A 90% reduction in size and weight
- Laptop supplies that can supply 12v at 5 to 10 amps
- Universal inputs 115V to 240V AC
- also run on 150 to 330 VDC
- Hybrids and Electric Vehicles have Kilowatts of 150 to 330 VDC available
- Home grid-tie solar has Kilowatts of high voltage DC available
- 12VDC to 120VAC inverters are now sine and modified sine at 90%+
efficiency 8) * These internally run on 200 VDC or so. Easy to run great distances on small wire if you run them directly on HV DC derived from your Hybrid or Solar.
CONS: with today's litigious society and general ignorance (compared to the vacuum tube days when even cub-scouts built 2 tube radios with High Voltage), it is doubtful that QST will publish the article. They have rejected it before, but I keep whittling away at the details.
Bottom line, is that high efficiency high voltage DC is everywhere and because everything runs on switching power supplies that run internally on HV DC and regulators that accept a wide range of input, then HV DC could be the new universal power source.
Problem is, Hybrid and EV MFR's are not going to provide access to HV DC willingly due to safety an liability issues. Same for Solar installers.... Same for QST.
But you can get some of what I am writing about on this page: http://aprs.org/FD-Prius-Power.html http://aprs.org/alternative-energy.html
For example, buried in a Camry Hybrid is a nice compact stand-alone 14 volt 100 AMP DC/DC supply. Input can be 200 to 350 volts DC (which you can get from 120V or 240VAC with just some diodes).. Problem is, it is bolted to the $1000 salvage battery and the salvage guys won't sell it separately.
The Prius 100amp 14v supply is integrated into the huge drivetrain inverter and inseparable from that $3000 unit (salvage cost).
As we electrify transportation and anyone with good sun goes solar, HV DC will be something Hams will be getting used to again.
Bob, Wb4APR
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I am rebuilding my 4.2kV PS for the 2m-8877. Does that qualify? QST still publishes high-power tube amplifier designs in their handbook. What's 150-250v amongst friends? Of course HV DC can badly burn or Kill you.
I was 14 years old when working on my DX-35 with 850vdc on the 6146 plate.
I agree that many hams these days aren't not trained to handle high-voltage with all the 12vdc solid-state electronics available. But QRO sspa are running at 50vdc and higher. There are rules for safe work on HV...time to review them.
73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw*, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubususa@hotmail.com ====================================== *temp not in service