I have posted some pictures of the hi pot test setup of my new Eimac YC-179 vacuum tube (MRI pull). This is for a future legal limit (LA amateur regulations) amplifier for digimode and contest CCS amateur radio use. It is better to run a tube cool than to stress a smaller tube for high dutycycle modes. Let’s hope the tube behaves OK. It measured less than 15uA at 16KV DC from A to G so I might have a good pull. (The reason for measuring at such a high voltage is to ensure that the swing that the PI circuit contributes when driven by the tube can be tolerated w/o breakdown).
HV setup to test to 16 KV (below)
Tube in the test rig (below)
Click on the pictures to see the gallery (below)
The HV meter to the left is on the hot side of the rectifier / smoothing cap and has a multiplier shunt that gives 200 x. That means that 80 on the meter on the left indicates 16KV (DC) output. The uA meter on the right is in line and measures leakage current. (uA) The o/p is current limited on this output. The meter panels are insulated with plexiglass and air gaps to prevent arc overs to the operator. Not that this would help since the HV leads are exposed. However in a future version… (below)