The Allen-Bradley 150-N4A Smart Motor Controller (SMC) is a micro-processor soft starter that is designed to maximize the effectiveness of the motor starting and stopping modes. The 150-N4A Controller utilizes 6 silicone-controlled rectifiers, that are divided up into 2 rectifiers per phase to control the conduction period and to control the torque to the motor when it is starting, running, and stopping. This starter comes with numerous advanced power monitoring and starter/motor protection features, which assist in increasing its overall reliability. The controller’s 3 connection ports house the network communication, additional I/O, or parameter configuration devices to enable its scalability. The scalability is also affected by the controller’s configuration through different options such as a multilingual 20-HIM-A6 controller/panel-mount keypad with an LCD screen. There is also a network capability and PC-based optimal configuration features.

The front panel of the 150-4NA Controller has one multicolored LED status indicator which gives the users both controller status and diagnostics information, and there is a Hold-to-Test/Push-to-Rest pushbutton that allows the users to reset the controller manually in case of a fault. Moreover, the button also initiates a turning cycle and test for fault. If one of the controller’s inputs is configured for an Emergency Run, and then the fault is activated, all system faults are disabled. As a result, the whole system will not shut down because of a fault. The 150-4NA Controller has the capacity to control connected resistor loads directly and this happens by using phase-angle control, depending on a certain reference value. Selecting this control method allows the controller to vary the output voltage as a response to the changing reference source. The reference source is programmable and very flexible.