I have a brand new walking treadmill that triggers circuit breakers when the treadmill electronics are powered on but when the treadmill motor is NOT running. The strange thing is that it triggers circuit breakers on circuits it is NOT plugged into.
My office and living room are on separate circuits. I plug the treadmill into a socket in my office and power on the electronics (but not the treadmill motor) and the living room breaker is triggered. Sometimes it happens immediately, sometimes it takes a few minutes, sometimes it doesn't happen for at least 30 minutes (so far at this point even with the motor running with me walking on it).
On one occasion it did trigger the office breaker while plugged into an outlet in the office (but this has only happened once, whereas the living room circuit has triggered instead on about 10 other tests).
UPDATE: Running the motor seems to prevent the circuit breakers from trigering. I walked on the treadmill for about an hour and a half and the breaker only triggered a few minutes after I switched the motor off but left the electronics on.