Write short notes on: (Any two) 2x5 a) Speed Control of DC Motor b) Color coding of resistors c) Power in purely inductive circuit POKIIARA UNIVERSITY Level; Bachelor Semester: Fall Year =: 2023…

Write short notes on: (Any two) 2x5

• a) Speed Control of DC Motor
• b) Color coding of resistors
• c) Power in purely inductive circuit POKIIARA UNIVERSITY Level; Bachelor Semester: Fall Year =: 2023 Programme: BE Full Marks: 100 Course: Basic Electrical Engineering (New) Pass Marks: 45 Time 23 hrs. Candidates are required to give their answers in their own words as far as practicable, r——_ The figures in the margin indicate full marks. coM er oEnotes a ac errr rp 1. a)” With the help of single line diagram, explain generation, transmission, and distribution of electricity in Nepal.

OR

Explain the present energy scenario in Nepal. i bf Why do we need color coding of Resistors? Find the equivalent resistance of the following circuit. 40 A 40 40 rrr NS — 40 oul c iy _[ ° 40 40 BAYA \ NN 2. Determine the current in 5 Q resistor for the circuit shown using Superposition Theorem (Figure 22). 20 20V ; 50 30 10A 10 tov Figure 22 @ Calculate the value of R that will absorb maximum power from the circuit (shown in the figure). Also calculate the maximum power drawn by it. 102 f 252 4 cov @) 20Q 52

OR

Using mesh analysis, solve for li, 2, Is. 10V 4a@ 22 122 8V = C9 Determine the V; and V2 using Nodal Analysis method. Also determine the current flowing through 30 Q resistor (Figure 19) o_| oo S" wo + +V1- + V2 - : ov = + T 302 ~—s«6OV Figure 19 : : ies KL

• b) Find the average value, rms value of the voltage waveform given below. esi staid soni ah Beica ; ie Pe Nexis ale ae P| Qe 7 | Al See Ne a Tena nati 20S) oR) 4. a) What will be the case for resonance in series RLC circuit? Derive the resonant frequency for this case. (oy A circuit have following electrical components in parallel: a) a resistor of 500 ohm, b) an inductance of 2H, c) capacitor of microfarad. In this circuit 200V, 50 Hz source is applied. Calculate:
• i) the total current drawn from the supply
• ii) complex power ili. active power
• iv) reactive power
• v) power factor of the circuit Dp The star connected stator of three phase, 50 Hz alternator suppliesa balanced delta connected load. Each phase of the load consists of a coil of resistance of 15Q and inductance 36mH and the phase voltage generated by the alternator is 231V. Calculate: i, _ the phase and line currents,
• ii) the load power factor
• iii) the power delivered to the load.
• b) An ideal 25 KVA transformer has 500 tums on the primary winding and 40 turns on the secondary winding. The primary winding is connected to a 3.3 KV supply. Calculate:
• i) The secondary emf.
• ii) The primary and secondary currents on full load.
• iii) The maximum core flux. 6. a) .Explain the operation of transformer on load and also draw phasor diagram at lagging power factor. rH fp A 220 Volts de shunt motor draws a current of $ A, and runs witha 8 Ns speed of 1500 rpm at no-load. When the motdr is loaded, the speed drops to 1400 rpm. Calculate the current drawn by the motor at loaded condition. Given that the armature winding resistance is 0,2 and field winding resistance is 110 2. 7. Write short notes on: (Any two) 2x5 A Voltage divider Rule b)/ Sources of Energy . c) Operation of DC motors’ a