D
DillonCo
- Jan 1, 1970
- 0
I need to limit current on "wall power" (115V, 60Hz) to 15A. A resistor
won't work because of the current and resulting voltage drop. An inductor
won't either simply because I'd need .02H (hard to get at 15A) and I have no
way of measuring inductance. I therefore decieded to use a capacitor. The
problem is that I need about 350uF in a non-polar cap at a reasonibly high
voltage (something I don't have).
I tried (as a test) connecting a 4.7uF 250V polarized cap in series with a
diode (to prevent reverseing), but this resulted in the cap exploding after
a couple seconds. There was no load (a short). I also connected a diode in
parallel with a similar cap so reverse current would flow through the diode.
I
put two of these in series swith the diodes opposing (so current wouldn't
just drain through them), and connected it again with no load. This time
the diodes (both!) exploded after a short time. I even tried two .05uF caps
in parallel, but one of these exploded when the power was turned on
(probably just caught the wrong part of the sine wave).
What am I doing wrong, and how can I successfully limit current?
Thanks.
won't work because of the current and resulting voltage drop. An inductor
won't either simply because I'd need .02H (hard to get at 15A) and I have no
way of measuring inductance. I therefore decieded to use a capacitor. The
problem is that I need about 350uF in a non-polar cap at a reasonibly high
voltage (something I don't have).
I tried (as a test) connecting a 4.7uF 250V polarized cap in series with a
diode (to prevent reverseing), but this resulted in the cap exploding after
a couple seconds. There was no load (a short). I also connected a diode in
parallel with a similar cap so reverse current would flow through the diode.
I
put two of these in series swith the diodes opposing (so current wouldn't
just drain through them), and connected it again with no load. This time
the diodes (both!) exploded after a short time. I even tried two .05uF caps
in parallel, but one of these exploded when the power was turned on
(probably just caught the wrong part of the sine wave).
What am I doing wrong, and how can I successfully limit current?
Thanks.