On Thu, 07 Mar 2002 09:48:26 -0600 Lynn <no9z@soltec.net> writes:
> Hello,
>
> Interesting discussion on glitch resistors...
> I have a HV ps with 10 1800 uf @ 450 volt filter caps. So I
> am assuming that the total capacitance for the B+ is 180UF
>
> Question
> I am using a variac to bring the HV up to 3000 vdc slowly. Is
this
> too much capacitance for a stepstart circuit?
Hi Lynn,
Nope. It will just take a bit longer to charge your large C.
A "standard" wirewound resistor is rated for about 10X overcurrent, in
a short time situation.
You didn't mention whether you are running from 110 or 220 volt power
...
Assuming 220 volts, a 20 ohm 250 watt R should work fine. If you
have space constraints, try one of the metal clad types which are a lot
smaller than the typical resistors as they are only rated for about 1/5
of their stated power unheatsinked.
Incidentally, I fuse my step start R's to avoid exploding the part in
the event the step start circuit takes the day off. :-)
73 & Good morning,
Marv WC6W
*
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