BigPatents India

A position-reporting device for, for example, a motor drive of a tap selector switch serves to detect the instantaneous position of the tap selector switch and to pass on this information in the form of an electrical signal. The device comprises a mounting plate (1). which carries fixed reporting contacts (11) arranged in a circle and a continuous contact ring (12) arranged concentrically with this circle, and a rotatable cam disc (2). The disc (2) produces an electrical connection between individual ones of the reporting contacts (11) and the contact rings (12) by way of a contact bridge (23), the latter being connectible by way of a toggle switch (31) with a signal output line. The toggle switch (31) is actuable by a cam profile (22) of the cam disc (2) to so interrupt the connection between the ring (12) and output line in synchronism with movement of the bridge (23) between successive reporting contacts (11) that making and breaking contact with the contacts (11) can be carried out in a non-conductive state thereby to avoid generation of electrical arcing.