Incon 1250 Series Rotary Position Indicator

Another configuration commonly encountered is the Selsyn position indicator

(Figure 2). These tap position sensors are traditionally used with a Tap Position

Monitoring device such as the Incon 1250 series devices.

The Selsyn encoder is an electromagnetic device that resembles a small electric

 motor. Although using various configurations of internal windings, they typically

excite rotor winding(s), and induce AC signal voltages in the stator windings

which can be compared in amplitude and polarity to determine the angular

position of the rotor shaft.

The Tap Position Monitor generates the voltage signals supplied to the rotor

winding(s). It then measures the resulting signals from the stator winding to

determine the shaft’s rotational position. This informationis converted to a

tap number and displayed on the front panel numeric readout. An analog

current signal is also generated which corresponds to tap position.

The M-2025D Current Loop Interface module accepts this analog current

signal.