Originally posted by goddo31 Yay for Balda photos, they look good.
Thanks. I have another Baldix, the one with no rangefinder and an Ennagon f3.5 lens which I reckon is slightly better around the edges. Incidentally, I appear to have got my f's and 5's mixed up!
Originally posted by goddo31 What is the scene in that first photo? Something to do with a power station perhaps?
I'm a radio transmitter engineer and the pic is part of the high voltage smoothing enclosure that provides the 26kV d.c. supply for a 300kW shortwave transmitter. 11kV comes in off the mains, is rectified and smoothed with those capacitors there, and the choke at the back, and is protected, in the event of an overload, by what is effectively a big flashgun thyristor circuit: the unit with the incubator lamp - and cobwebs! - on it.
Sort of like the wall-wart to your laptop. But bigger...
A fault initiates a pulse which applies a 1us pulse to a thyristor, which in turn triggers a mercury-filled ignitron, which is held closed by a further 130ms 'sustain' pulse, and which dumps the 26kV stored energy in the capacitors down to deck via a resistor and, at the same time, opens the vacuum switches to remove the supply. I actually built a test-jig for the ignitron pulse unit with a flashtube from a disposable camera as it was easier - and cheaper - to detect a 1us pulse than haul a storage 'scope around with me.
Sorry - getting carried away a bit here...