Example 4.13 Using Superposition to Solve a Circuit

Use the principle of superposition to find v₀in

the circuit shown in Fig. 4.66.

A 200-kVA, 480-V. 50-Hz, Y-connected synchronous generator with a rated field current | of 5 A was tested, and the following data were taken:

• OC test-Terminal voltage = 540 V at rated field current of 5 A
• SC test-Line current=312 A at rated field current of 5A
• DC test - DC voltage of 10 V applied to two terminals, a current of 20 A was measured.
• The equivalent circuit of the synchronous generator is shown in Figure QL.

(a) Calculate the speed of the generator in r/min. 

(b) Calculate the generated emf per phase.

(c) Calculate equivalent circuit parameters (armature resistance and synchronous reactance) at rated field current of 5 A.

Find the values of the armature resistance and the approximate synchronous reactance in ohms that would be used in the generator model at the rated conditions. 

Find I_L

In a 33 kv bus, the voltage is 1 pu in a base line to line voltage is 33 kv. If a LLL-G Fault occurs at this bus, the fault current flowing to the bus is 30KA. The 3-phase MVA base is 100 MVA. whats the thevenin equivalent impedance seen looking to the net work.

The output signal from an AM modulator is u(t)=5 cos 1800πt+20cos 2000πt+5 cos 2200πt.

a. Determine the modulating signal m(t) and the carrier c(t).

The output signal from an AM modulator

u(t) = 5 cos 1800πt + 20 cos 2000πt + 5 cos 2200nt

a. Determine the modulating signal m(t) and the carrier signal c(t).

b. Determine the modulation index. 

c. Find the ratio of the power in the sideband to the power in the carrier.