Master switch

Where is this master switch used?

A master switch is a control device that switches the wiring of the control circuit according to a predetermined sequence. Main control devices are primarily used to switch control circuits; they are employed to send commands or signals in order to control the starting, operation, stopping, or state changes of electric drive systems and other controlled devices. Depending on the number of controlled circuits and the magnitude of the current, the control device can be operated directly or indirectly through intermediate relays. Command electrical devices are classified into five categories based on their functions: 1. Control buttons 2. Universal changeover switches 3. Limit switches 4. Command controllers 5. Other command electrical devices. In electrical drive systems, these devices open and close contacts in a specific sequence in order to issue commands or achieve interlocking of other control circuits. Based on their structural design, they can be divided into two types: cam-adjustable and cam-non-adjustable master controllers. Their operating principle is the same as that of universal changeover switches, with cams being used to control the closing of the contact system. The combination of cams of different shapes allows the contacts to act in a specific sequence, while the angle of rotation of the cams is determined by the structure of the controller; the number of cams depends on the requirements of the control circuit.