The operating principle of a cam pump is based on the inclusion of a group of contacts behind the additional drive of the device. By wrapping the handle in the required position, the drive turns around its axis and brings into action the cams, rotated on the new one. The stench, in its own way, freezes the singing group of contacts. To understand how a group of contacts operates, you need to look at the diagram that is based on the required connection diagrams. If the drive is in the required position, the jumper is fixed in place using a special fixing mechanism and the circuit begins its work. To turn to the zero position, you must turn the handle again.