[Amps] 3-500Z glitch resistor

[David G4FTC]

>> Everyone seems to agree that a glitch resistor between the plate choke
>> and the HV supply is a good idea, to limit huge current surges due to
>> arcs caused by gas, etc. But recommendations for the value seem to vary
>> all over the map.
>
> I like the look of Vishay RCH series or similar (Tyco do an
> equivalent). The 50W version is rated at 5.5W without heatsink and
> is specified to handle 2500Vrms (that's 3500V peak) short term
> overload. If you want to bolt it to a panel for heatsinking, the
> insulation is rated for 3500Vrms (5kV peak).
>
>


Checking page 4 of the datasheet for the RCH50 http://www.vishay.com/docs/50006/rch.pdf
shows a maximum overload capability of about 50 Joules.

A capacitor bank for a linear of 50uF charged to 3kV will deliver about 225 Joules and
under glitch conditions the resistor will be absorbing most of this power, more if
the power supply doesn't have glitch detection/protection and remains connected
to the mains.

In order words to be safe you'll need about five RCH50 resistors in series.

I don't know what energy the tube can absorb under flash over conditions without 
damage and this will also influence the selection of the resistor.

Regards

David G4FTC

_________________________________________________________________
Make a mini you and download it into Windows Live Messenger
http://clk.atdmt.com/UKM/go/111354029/direct/01/