Hi John,
We all know what we're doing!
Apart from the availability of a tree phase supply (nearly every German
household has a three phase system available, for the kitchen oven at
least, which an be tapped :-) ) the high DC voltages can be difficult
to handle because the voltage will be about 560V when using a B6
rectifier. However, for a H bridge design you could use 900V FETs which
are very common these days :-)
Quite interesting. It would be a chance for me to finally reach the 1W
ERP limit. Worth to think about.
73, Stefan
Am 28.11.2015 18:17, schrieb John Rabson:
Andy,
I have worked with three-phase systems in my career and
I agree with you that 3 phase can be useful – Provided You Know What
You Are Doing. Not only is it 300 Hz ripple but it can be as
low as 4.2% before you even start filtering.
Having met you, I have no doubt you take great care to
protect exposed parts, and take other essential steps.
What would worry me would be somebody tinkering with
such things and not knowing
where their areas of ignorance lay (the same goes for any high-voltage system).
John F5VLF
On 28 Nov 2015, at 17:26, Andy
Talbot <[email protected]> wrote:
What's wrong with that ?
Sounds an excellent idea for a QRO transmitter. 300Hz ripple - much
easier to filter out.
My 137kHz Tx runs from rectified (single phase) mains - the isolation
is provided in the ferrite output transformer and FET drive pot-core
A school we once went around with long leads and an AVO identifying
sockets to be found on all three of the phases. That was so that,
using extension leads, we could bring them all into the lab to get a
three phase motor running. Such interesting things could be done in
schools in the 1970's
Andy G4JNT
On 28 November 2015 at 15:52, John Rabson <[email protected]> wrote:
In the early days of 73 kHz I believe a Luxembourg station built a
transmitter which was powered off full-wave rectified three-phase mains
without an isolating transformer. NOT the best way of doing things!
John F5VLF
[email protected]
Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and
ROBSONNE
|
|
