[AMPS] Load C as last resort safety

[Phil Clements]

>
>My question: How long would it take a 10 ohm 10 watt high voltage
safety
>"fuse" that is in the B+ line to open in the event the plate bypass
cap did
>short and the load C saw the full anode potential?
>
>Just curious. Wonder how dangerous this is to the operator other than
the
>gun shot loud POP that happens when the resistors open scaring the
hell out
>of the unsuspecting ham (in this case Ku7i).
>
>Lane
>Ku7i

If the glitch resistor and safety RF choke are destroyed when the
plate
blocking cap shorts, they are not big enough!

The deal is this...when D.C. appears at the safety RF choke, it is
supposed to cause the primary circuit breaker or fuse on your
power supply without burning up the choke.

When a glitch occurs beyond the glitch resistor, it is supposed
to be  at the correct ohmic value and wattage to allow
any or all of three things to happen without destroying itself:

1. the primary CB's or fuses blow, shutting down the HV supply

2. bleed the energy in the filter capacitors down to a safe level
    in a very short period of time. (Just shutting down the primary
    is not enough; a lot of energy remains in the filter caps, and
    the normal bleeder resistor in the PS  is too slow to do the job.)

3. limit the current available to the RF deck in case of a short
    anywhere beyond the glitch resistor.


If any or all of the above  are accomplished  WITHOUT destroying
any components, (except the primary fuses) you have a properly
designed glitch resistor.  The glitch resistor was never meant to
perform like a fuse; it is there to limit current until the energy
from
the PS goes away.

(((73)))
Phil, K5PC



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