Re: another transformer question

<snip> for 48VDC so should just make it under 50V, but the
measurement says

> 60VDC, so should I risk it and go ahead to use the same capacitor,
> even if only temporary? What happens when one exceed the rated
> voltage of a capacitor?
>
> Thanks
>
>

In the short term normally nothing happens. If the overvoltage lasts
too long or is way over the limit of the working voltage things can
get interesting in a hurry. The insulation layer starts to break
down and the cap starts to draw excessive current which results in a
rapid build up in internal heat and the electrolyte starts to turn to
steam. Usually the result in larger caps is a hissing noise with
gook flowing out of the cap. The cap can explode (smaller ones go
off like firecrackers) but the real danger is to down stream
components. If you loose the filter cap the electronics running off
of it are essentially running off half wave AC at 120HZ...not kind to
components expecting nice smooth DC!

A lot of transformers are designed and rated at close to full load to
account for losses in the windings and other magnetive things, so a
36VAC unit might go to 40VAC lightly loaded but 45Volts sounds
excessive. Your two 12VDC fans in series should really be spinning
at 60VDC! The resistor in series will reduce that some but you may
have to increase the value to keep the voltage across the fans 24VDC.