The gear of the servo motor rotates the rotor of the control transformer The error signal is applied to the differential amplifier which gives input to the servo motor. The voltage equation shown above is equal to the shaft position of the rotors of control transformer and transmitter. The synchro transmitter and the control transformer together used for detecting the error. On substituting the value of angular displacement in equation (1) we get The small angular displacement between their rotor position is given as The rotor terminal voltage of the Synchro transformer is given as The total angular separation between the rotors is Φ = (90º – θ R + θ C) An angle θ R deflects the rotor of the transmitter and that of the control transformer is kept θ C.
The above figure shows the zero position of the rotor of transmitter and receiver.Ĭonsider the position of the rotor and the transmitter is changing in the same direction. Φ – 90º the axis between the rotor of transmitter and control transformer is perpendicular to each other. Where φ – angular displacement between the rotor axes of transmitter and controller. The voltage generates by the rotor of control transformer is equal to the cosine of the angle between the rotors of the transmitter and the controller. The flux axis of the control transformer and the transmitter is aligned in the same position. Because of the circulating current, the flux is established between the air gap flux of the control transformer. The current of the same and magnitude flow through the transmitter and control transformer of the synchros. The output of the transmitter is given to stator winding of the control transformer which is shown in the above figure. The zero position of the rotor is used as a reference for determining the rotor angular position.
When the rotor angle becomes zero, the maximum current is produced in the stator windings S 2. The variation in the stator terminal axis concerning the rotor is shown in the figure below. The three terminals of the stator windings are The rotor axis makes an angle θ r concerning the stator windings S 2. The figure below shows the rotor position of the synchro transmitter. Let V s1, V s2, V s3 be the voltages generated in the stator windings S 1, S 2, and S 3 respectively. The voltage is induced in the stator winding. The flux linked in the stator winding is equal to the cosine of the angle between the rotor and stator. The voltage is induced in the stator winding because of the mutual induction between the rotor and stator flux. The voltage applied to the rotor induces the magnetizing current and an alternating flux along its axis. The constructional feature of the synchros is shown in the figure below.Ĭonsider the voltage is applied to the rotor of the transmitter as shown in the figure above. The AC voltage is applied to the rotor with the help of slip rings. The rotor of the synchros is a dumbbell in shape, and a concentric coil is wound on it. The coils of the stator windings are connected in star. The AC voltage is applied to the rotor of the transmitter and it is expressed as The axis of the stator winding is kept 120º apart from each other. The stator is slotted for housing the three phase windings. The stator of the synchros is made of steel for reducing the iron losses. Synchros Transmitter – Their construction is similar to the three phase alternator. The detail explanation of synchros transmitter and receiver is given below. The synchro always works with these two parts. The controls synchros is used for error detection in positional control systems. The control type Synchro is used for driving the large loads. This type of synchros has small output torque, and hence they are used for running the very light load like a pointer.