a device for closing and opening electric circuits in systems of automatic control by electric drives. A positional switch is actuated by the motion of the mechanism itself. At various points in its travel, the mechanism opens or closes the appropriate contacts of the switch. The operation of the contacts causes signals to actuate the control devices of an automated electric drive.
The simplest and most widely used example of a positional switch in a control circuit is a switch that prevents a mechanism from traveling beyond its normal end position. In this case, the positional switch is called a limit, or end, switch. Positional switches are classified according to their principle of operation as contact (electromechanical) switches and contactless switches, such as induction and capacitance switches.
REFERENCESKomar, M. A. Osnovy elektroprivoda i apparaty upravleniia, 3rd ed. Moscow, 1968.
Ivenskii, Iu. N. Beskontaktnye putevye perekliuchateli v promyshlennoi avtomatike. Moscow, 1971.
G. G. NESTEROV