STUPIDSID
1 (a)
Derive an emf equation for transformer with usual notation.
7 M
1 (b)
A shunt generator deliver 195 A at 250V, armature and shunt field resistances are 0.02Ω and 50Ω respectively. The iron and friction losses are 950W. Calculate (1) Emf generated, (2) Total copper loss, (3) Output of prime-mover, 4) Mechanical efficiency, electrical efficiency and total efficiency.
7 M
2 (a)
Explain Hopkinson`s test with its advantages & disadvantages.
7 M
Answer any one question from Q2 (b) & Q2 (c)
2 (b)
Explain O.C & S.C. test on 1-ϕ transformer.
7 M
2 (c)
A 200V 4-pole lap wound DC shunt motor has 800 conductors of its armature winding. The armature and field winding resistances are 0.5 Ω and 200 Ω respectively. Motor takes 21A and flux /pole is 30mwb. Find the torque and speed of the motor.
7 M
Answer any two question from Q3 (a), (b) & Q3 (c), (d)
3 (a)
Explain the constructional details of transformer.
7 M
3 (b)
A 200 V dc shunt motor develops an output of 17.158 kW, when taking 20.2 kW. The field resistance and armature resistance are 50 Ω and 0.06 Ω respectively. What is the efficiency and input power if output power is 7.46 kW?
7 M
3 (c)
List the methods of speed control of DC series motor, explain any one in detail.
7 M
3 (d)
A 40 kVA, single phase transformer has 400 turns on primary and 100 turns on secondary. The primary is connected to 2000 V.50 Hz supply. Determine: (i)The secondary Voltage on open circuit. (ii) The current flowing through the two windings on full load.(iii) The maximum value of flux.
7 M
Answer any two question from Q4 (a), (b) & Q4 (c), (b)
4 (a)
Write a note on T-T connection for 3-ϕ transformer.
7 M
4 (b)
A 600 kVA, 1-phase transformer has an efficiency of 92% both at full-load and half-load at unity power factor. Determine its efficiency at 60% of full load at 0.8 power factor lag.
7 M
4 (c)
What is DC motor? Derive its torque equation.
7 M
4 (d)
A 10 KVA, 2000/400 V single phase transformer has R1=5Ω, X1=12Ω, R2=0.2Ω and X2= 0.48 Ω. Determine the equivalent impedance of the transformer referred to (1) primary (2) secondary side
7 M
Answer any two question from Q5(a), (b) & Q5 (c), (d)
5 (a)
Describe parallel operation of transformer.
7 M
5 (b)
Explain the O.C.characteristic of DC shunt Generator, also define the critical resistance & speed from the characteristic.
7 M
5 (c)
Explain 3-point starter for DC motor.
7 M
5 (d)
Explain the transformer ON-LOAD with vector diagrams.
7 M
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