Manual Controllers:

A manual controller, described through Figure, is a controller whose contact assembly is operated through mechanical linkage from a switch-type handle or a pushbutton arrangement. A controller is operated through hand.

The manual controller is given along with thermal and direct-acting overload units to protect the motor from overload conditions. The manual controller is generally an "ON-OFF" switch along with overload protection.

Manual controllers are normally used on small loads such as machine tools, fans, blowers, compressors, and pumps. These categories of controllers are simple, and they give quiet operation. The contacts are closed simply through moving the handle to the "ON" position or pushing the START button. That will remain closed until the handle is moved to the "OFF" position or the STOP button is pushed. A contact will also open if the thermal overload trips.

Manual controllers do NOT gives low voltage protection or low voltage release. While power fails, the manual controller contacts remain closed, and the motor will restart while power is restored. This characteristic is highly desirable for small loads since operator action is not required to restart the small loads in a facility; thus, it is undesirable for larger loads since it could cause a hazard to equipment and personnel.

Figure: Single Phase Manual Controller