01 February 2021
How does a thermal-magnetic trip unit work in a circuit breaker?Product Line:
Miniature and Molded Case Thermal-Magnetic Circuit BreakersResolution:
Thermal magnetic trip units trip under short circuit conditions instantaneously, with no intentional delay. Below the instantaneous trip current, they have a delay established to protect conductors while allowing momentary current surges such as for motor starting and transformer inrush. In some cases, they have adjustable instantaneous trip current settings.