The breaker may have both modes. The magnetic opens instantaneous on peak current while the thermal has a time delay.
I'm not sure the thermal breaker trips on rms current. I'm guessing not. The breaker trips on power dissipated in the thermal element.
P(t) = (i(t))^2 * R.
i(t) is instantaneous current as a function of time
R is the resistance of the thermal element
Two waveforms may have identical rms current, but the waveform with the greater peak current will create more heat in the breaker. For example one wave has a peak of 1A and the other has a peak of 2A. Since current is squared, the 2A wave generates 4 times the instantaneous heat.
road-runner wrote:
I would have thought that in either its magnetic or thermal mode, a breaker would trip based on RMS current as opposed to peak current. Bad logic?
