Mike,
Your bleeder resistor is too small.
4000 volt transformer with fullwave bridge should
produce at least 5600 volts no load.
5600 volts across 100K -> 56 ma
56 ma * 56 ma * 100K = 313.6 watts
313.6 watts >> 225 watts
At a minimum, you need either: (1) a pair of those resistors
in series, (2) a 200 K 225 watt bleeder or (3) a 100K 500 watt
bleeder. Even then, you will be not have a lot of safety
factor and probably need to provide cooling for the bleeder.
Safer yet would be a (series) string of four 50 K 225 watt
bleeders.
Finally, is the resistor rated for > 5 KV? Most are not.
73,
... Joe, K4IK
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On Behalf Of aborg
> Sent: Sunday, April 24, 2005 9:44 AM
> To: Amps Amps
> Subject: [Amps] Bleeder Resistor Inquiry
>
>
> I am currenty building a HV Power Supply using a
> 4800vac pole pig, 40uF 5kv oil filled cap , 10kv PIV
> rectifier board, 20 amp variac and a 100k 225watt
> bleeder.
>
> The initial power up started well without the bleeder
> connected to the circuit after 30 min burn-in no
> problems. Discharged the circuit and added the 100k
> bleeder and 5 mins the bleeder starts to smell and the
> exterior paint starts to bubble. Shut it down and
> examined the circuit, all seem accurate.
>
> Question : Is my bleeder to small ?
>
> P.S. : The variac was set at 4KV at all times.
>
> Mike-KK4MS
> a_borg@yahoo.com
>
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