BWH is a molded wirewound device. Pretty good writeup here: http://n8sfc.com/bwh.html For high surge applications, you don't want conventional film resistors; they fail under normal conditions. WB2WI
The MOF resistors we use in our suppressor retrofit kits are rated by Matsushita at 100-ohms, 3W, 70ºC. In free air, they will dissipate 12W for one hour with a resistance change of less than 10
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, won
But that's only 35V across them. Many metal film resistors are a spiral on the form, and the gaps might arc if hv beyond the rating is applied. I'm with you all the way on their capacity to withstand
Gents, HV safety resistors absorb glitches of the amplifier tubes, such as internal arcs. In such a situation the resistor may be absorbing the entire stored energy of the power supply filter and att
Hal, I fixed the rings arcing on a big open frame, 500 HP synchroness motor in ACF that way once. When you would apply the 4160 Vac on the stator, it acted like a big transformer and caused an arc on
Good point, but the typical potential in suppressor service is only a few tens of volts and there are < two turns of MOF. Richard L. Measures, AG6K, 805.386.3734. www.somis.org ______________________
C-discharge arcs in a vacuum are quite quiet, however, in air such arcs make a big bang. Glitch resistors should pass the big screwdriver test before they are trusted with an expensive vacuum tube. R