That is interesting, I'm impressed. But why didn't OSHA catch that?In the case at the heat treat furnace, there was a fan belt from the motor to the fan blade. The belt failed to heat issues and probably slipped in the pulleys causing it to break. When that happens, the motor current goes from normal run current to almost zero.
The hi/lo motor current trip alarm allows a bandwidth to be set for low conditions signifying a problem as well as an overcurrent that signals the motor is failing and drawing too much current. Either situation shuts the system down.