Magnetrons can have a variety of failure modes, I'm trying to come up with a better test besides applying high voltage in a system and blowing fuses, or blindly swapping it out for a new one when an industrial oven detects over current / blows line fuses (480V 3Ph system, fuses are not cheap, changing Magnetrons is not easy).

When performed by a trained individual with appropriate safety measures in place, would a Megohm meter (say 5kv) be useful to help determine if a Magnetron is going to arc internally due to damage when it has a similar anode voltage rating to the Megohm meter?

This test would be performed after verifying the following:

  1. The filament has continuity.
  2. There is not continuity between the HV terminals and case/ground.
  3. There is no apparent thermal damage or antenna damage.
  • \$\begingroup\$ You mean a "Megger" type insulation test meter? \$\endgroup\$ May 15 at 17:48
  • \$\begingroup\$ I think maybe. I can imagine arcing that happens only with the filament on and/or with reflected power. Disclaimer, I haven't used magnetrons. Haven't seen a 5 kV megohm meter but I would treat one with considerable respect. \$\endgroup\$
    – Fred
    May 16 at 0:41
  • \$\begingroup\$ Ultimately, a megger shows how insulation changes over time, so it's more a regular maintenance tool than a genetal fault detection tool. One measurement is meaningless. It depends on how the arc is formed. \$\endgroup\$ May 16 at 20:26
  • \$\begingroup\$ Megger is a manufacturer of test instruments. The eponymous instrument is merely a high voltage low current ohmmeter. Changes over time is not intrinsic to the resistance measurement. You can quite easily measure insulation performance with it. \$\endgroup\$
    – MrGerber
    May 24 at 11:04
  • \$\begingroup\$ @Fred At the time of writing, Megger has insulation resistance testers in their lineup with measurement voltage at least up to 15kV \$\endgroup\$
    – MrGerber
    May 24 at 11:07


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