[Amps] Too much filtering

[Radio WC6W]

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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