6 Feb
2006
6 Feb
'06
5 p.m.
On 06/02/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
It is a very bad idea to 'run up' a swtich mode PSU (which this is) on a
Variac. SMPSUs appear as conatant power loads, as the input voltage
decreases, the current increases. Some supplies will blow their chopper
transistors under such conditions.
Having witnessed the effect of a sustained brownout (I think it went down
to 50V for about 15 minutes) on a UPS-less machine room full of kit with
240V switched mode PSUs, I know that's a no-no. I think the survival rate
was about 20%.
--
Pete Edwards
"Prediction is very difficult, especially if it's about the future" - Niels
Bohr