Problem 1:

A two-phase servomotor has rated voltage applied to its excitation winding. The torque speed characteristic of the motor with Vc = 220 V, 60 Hz applied to its control phase winding is shown in Fig.1. The moment of inertia of the motor and the load is 5×10^-5 kg.m² and the resultant motor-load viscous friction coefficient is B = 0.002 N.m x s / rad .

a) Write the torque equation and draw the block diagram of the motor with and without load.

b) Find the shaft speed and position response to the step voltage V_c = 220 V applied to the control phase winding when no load is applied.

c) Find the shaft speed and position response to the step control voltage V_c = 220 V if the load is applied of TL = 0.0003ω²m.

d) Compare results obtained for operating conditions b) and c) and make comments.

Problem 2: In Fig.2 (below) a radar antenna is controlled by the position system with two- phase induction servomotor. Let the transformer selsyn system and the potentiometer transducer give a voltage of 1V per radian of position. The transfer function of the servo amplifier is G(s)= 10(5+0.01571s)/7+s.

Assume that the initial angular position of the radar is zero. The transfer function between the motor control phase voltage Vc and radar position

θ is M(s)= 2.733/s(1+0.01571s)

a) Draw the block diagram of the system

b) For step change in the command angle of 120^o find the time response of the angular position of the antenna.

c) Find step response if transfer function G(s) has changed to:

G(s)= (10(0.8+0.01571s))/(7+s)

d) Compare results obtained for operating conditions b) and c) and make comments.

Attachment:- HW.rar