Hello Everyone, due to a kind gift from Mr Beckett, I now have a decent variac, what I would like to try is to reform some caps, mainly electolytic smoothing caps.
I have trawled google and come up with loads of options, and would like to know the best way to do this, is it possible to reform them in place, say a radio, by pulling the valves and winding the power up slowly, metering the ampage across the cap, or is it best to remove the cap and use a suitable diode and meaty resistor, measuring the voltage across the resistor and the cap, I am so confused, with so many options as there are on google.
What would you suggest?
Paul
on the gallery under homebrew is Rob T's variac reformer made in a bread bin, perhaps we could persuade him to give some details and schematics?
cheers Mark
That is a splendid idea Mark.
It wasn't that kind as I extracted an EKCO U354 from him
I favour an isolation transformer after the Variac plus a diode, a big resistor and an AVO to measure the current.
Alan
i will dig out the circuit its very simple mine has switching so the variac can be used with out the reformer feeding a 13 amp socket, so i could soft start solid state tvs ,lamp limiters dont work well with sets that use degausing circuits
rob t
Thank you Rob t, much appreciated.
(21-11-2011, 10:18 PM)AlanBeckett Wrote: [ -> ]I favour an isolation transformer after the Variac plus a diode, a big resistor and an AVO to measure the current.
Sounds quite feasible, but wouldn't it be better to put the isol. transformer first, then the Variac, on the grounds of safety?
Just a thought ~ or have I come to the wrong conclusion with confidence - again! :embarassed:
Al.
Al,
I don't supose it matters. It's just that I've got my Variac permanently wired into the mains, and as it's a big one I wouldn't want the switch-on surge to go through a small transformer, which is all you need for reforming.
Alan
O.K. Alan - point taken. You and I have the opposite arrangement of distributing a mains supply to our respective work-benches. In my case, I have a 2.5 kVA isol. transformer complete with D.P.S.T switch, fuses & an RCD & that then feeds a 'Variac' (with a 5A fuse in its outlet socket). That transformer also feeds assorted sockets independently. Mind you, that Variac is a big one: you're quite familiar with it, of course!
Al.
(21-11-2011, 09:59 PM)Mark Ryding Wrote: [ -> ]Paul
on the gallery under homebrew is Rob T's variac reformer made in a bread bin, perhaps we could persuade him to give some details and schematics?
cheers Mark
Paul,
I would agree with this approach, too. Using Rob T's or Joe's lamp limiter is the safest way to start your project.
Regards,