The 140U-JTD3-D22 circuit breaker is a thermal-magnetic circuit breaker that has been designed and distributed by Allen-Bradley. This breaker has a rated operational current of 225 Amps and a different thermal current rating and magnetic current rating of 1125 Amps and 2225 Amps, respectively. The breaker employs these two current detection methods to detect different kinds of current, for example, for short-circuit current. These detection mechanisms consist of the use of two metal bars that get heated by the current for the thermal mechanism and of magnets for the magnetic mechanism. The Allen-Bradley 140U-JTD3-D22 thermal-magnetic circuit breaker has different breaking capacities that depend on the voltage applied, for example, 80 kA at 220 Volts and 30 kA at 690 Volts and with a frequency of 50 Hertz.

The Allen-Bradley 140U-JTD3-D22 thermal-magnetic circuit breaker has an interrupting rating of 85 to 180 Amps with voltages of 200 to 600 Volts, respectively. All of these values are easily modified by the voltage that is applied. It is recommended to select a compatible motor and perform different compatibility tests before acquiring and installing a circuit breaker of this kind. The Allen-Bradley 140U-JTD3-D22 thermal-magnetic circuit breaker comes with three poles and it belongs to the J frame product line of the series. There are different accessories available such as end caps kits, phase barriers, plug-in adapters, DIN rail adapters, and multi-tap terminal lug kits that can be used to enhance the performance of this breaker. These accessories are included in the series catalog. The maximum operating temperature of this breaker is 75 degrees Celsius if it is properly derated. If it is intended to be used with its maximum efficiency levels, the maximum operating temperature is 40 degrees Celsius.