Magnesyn

a contactless sensor (transducer) of the angular position of a shaft. It is used for telemetry of the readings of measuring instruments and of the angle of rotation of a shaft when only negligible loading on it is permissible—for example, in magnetic compasses.

A magnesyn consists of a stator and a rotor (a permanent magnet that is mechanically connected to the object being monitored). The stator windings are connected to an AC source at a frequency of 400-500 hertz. For telemetry, two identical magnesyns are used (a transmitter and an indicator), with electrically connected stators. When the rotor of the transmitting magnesyn is turned, an additional electromotive force appears in its stator winding, and a circulating current flows along the connecting wires, producing an adjusting (synchronizing) torsional moment in the stator of the indicator magnesyn. In such a system, when the shaft of the transmitting magnesyn is rotated through a certain angle, the rotor of the indicator magnesyn is rotated through the same angle (to a “matching” position), since the shaft of the transmitting magnesyn has been stopped.

Magnesyns are occasionally used with a selsyn to form a magnesyn-selsyn servosystem. In this case the magnesyn is connected to the drive shaft, and the selsyn with the driven shaft. When used as an element in a servodrive the error of a magnesyn is about 0.25°.