A Bionaire air purifier with ionizer works fine in a location without
Earth Leakage Circuit Breaker (ELCB = RCD, RCCB, GFCI, GFI, ALCI), or
with an isolation transformer, but trips the ELCB immediately if
plugged in with an ELCB. Resistance between neutral and earth varies
between 40 to 80 ohms. Is there any most obvious culprit before I open
it (e.g., radio interference suppressor capacitor; motor shorted to
frame)?

By the way, when the purifier got plugged in and tripped the ELCB a
"wall wart" 5V 2A switching power supply (for WiFi access point) died
at exactly the same time - is this something others have had? I've not
seen it before. I doubt it's coincidence.

Best wishes,
Michael [Email address above no longer valid (used to be)]