The Allen-Bradley/Rockwell Automation 140G-J3F3-D15 circuit breaker is a 3-phase circuit breaker. It has a current range rating of 150 Amps, it supports a maximum voltage of 600 Volts AC, and has a breaking capacity or interrupting capacity of 35 kiloAmps at a voltage of 480 Volts AC. The interrupt capacity of a breaker is the amount of fault current that it can safely interrupt without damaging itself. The 140G-J3F3-D15 circuit breaker has an adjustable thermal/adjustable magnetic trip unit. Note that the trip unit is the brain of the breaker. The unit functions by tripping the operating mechanism when a short circuit occurs or when there is an extended overload current.

The Allen-Bradley 140G-J3F3-D15 circuit breaker’s trip unit uses a temperature-sensitive device combined with an electromagnetic device to provide protection to the electrical circuits. For the frequency, the 140G-J3F3-D15 circuit breaker retains the same tripping functionalities when it is used in a system with a frequency of either 50 Hertz or 60 Hertz. However, with higher frequency systems, the 140G-J3F3-D15 circuit breaker may need to be derated to recalibrate. The 140G-J3F3-D15 circuit breaker has 3 poles, indicating that it supports 3-phase distribution systems. The 140G-J3F3-D15 circuit breaker has a molded case and its maximum operating ambient temperature is rated at 40 degrees Celsius. Note that the reliability of the 140G-J3F3-D15 circuit breaker can be highly affected by extreme differences in the surrounding temperature since the breaker’s trip unit is temperature-sensitive. For example, at an ambient temperature above 40 degrees Celsius, nuisance tripping is likely to occur and dangerous temperatures may be present at the breaker terminals.