Question

QUESTION 2 [20 marks] (i) [10 marks] A 120-V dc generator energizes a motor whose coil has an inductance of 50 H in series with a resistance of 100 2. A field discharge resistor of 400 2 is connected in parallel with the motor to avoid damage to the motor, as shown in Figure 3. Find the current through the discharge resistor 100 ms after the breaker is tripped. (The circuit breaker has been in the closed position for a long time before opening at time t = 0). Circuit breaker 120 v Motor 400 S2 Figure 3 (ii) [10 marks] In the circuit of Figure 4, switch has been in the closed position for a long time before opening at time t = 0: a. (3 marks) Find the capacitor voltage v (0) and i(0) for t < 0. b. (7 marks) Give an expression for the capacitor voltage v.(t) and i(t)(i.e., as a function of time) for t > 0. 40250 302 w 80 v 3F+ 0.5i 502 Figure 4

Answer 1

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