On Nov 1, 2005, at 7:54 AM, HAROLD B MANDEL wrote:
> Gents,
>
> HV safety resistors absorb glitches of the amplifier tubes,
> such as internal arcs.
C-discharge arcs in a vacuum are quite quiet, however, in air such arcs
make a big bang.
> be absorbing the entire stored energy of the power supply
> filter and attempting to dissipate it as heat, which is
> the cause for many explosions.
>
> After reading AG6K's articles about this device, and by
> observing the quality of devices employed in commercial
> amplifiers it was decided to use a 225 Watt, 25-Ohm
> wire wound that resembled a cookie-cutter with wavy
> windings in my latest project. The power supply uses
> 50uF at 5KV capacitance and is rated at 3.0A CCS.
> The resistor is located in the power supply cabinet
> and away from any delicate stuff, so if it did explode
> little else would be damaged by grenading porcelain.
>
> If you choose to use a vitreous enamel wire wound
> resistor of whatever value, please make sure it's
> mounted in such a way that if it did explode it will not
> destroy tubes, vacuum caps, vacuum relays, etc.
Glitch resistors should pass the big screwdriver test before they are
trusted with an expensive vacuum tube.
>
> Some folks surround this resistor with a cane metal
> (perforated) enclosure.
>
> Hal
> W4HBM
>
>
>
>
>>
>> Hv safety resistors are in place to protect the tube or tubes not
>> the
>> diodes, who cares if a diode block goes compared to the price of a
>> tube. I
>> have a 25W resistor in series with the B+ explode, wonderful fuse
>> the tubes
>> survived, and so did the diodes. 73 Sam KF4YOX
>>
>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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