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A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
A
remain same
B
go down
C
improve
D
none of the above
Correct Answer:
improve
Read the following information carefully and answer the questions that follow: Seven persons Tina, Vini, Yasir, Rishi, Sanya, Pankaj and Urmila live on the separate floors of a 7- floor building. Ground floor is number one; second floor is number two and so on. Each of them goes to a city viz. Paris, Istanbul, Shanghai, Durban, London, Madrid and Dubai but not necessarily in the same order. Only three people live above the floor on which Sanya lives. Only one person lives between Sanya and the one who goes to Paris. Vini lives just below the person who goes to Madrid. Only three people live between the one who goes to Paris and London. The person who goes to Madrid lives on an even numbered floor. Urmila lives just above Rishi. Urmila does not go to London. Only two persons live between Pankaj and the one who goes to Durban. Pankaj lives above the person who goes to Durban. Yasir does not go to Istanbul. Tina does not live just above or just below Sanya. The one who goes to Shanghai does not live just above or just below Pankaj. Who among the following lives on floornumber 7?
A
Tina\
B
Yasir
C
Pankaj
D
Urmila
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the receiving end current at this operation mode will be _____________
A
526 A
B
549 A
C
521 A
D
580 A
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. The new sending end voltage at the half the voltage regulation is _____________
A
10.84 kV
B
11.84 kV
C
8.84 kV
D
16.2 kV
Assume a 275 kV transmission line having the following line constants:A = 0.85∠5° ; B = 200∠75° If a load is connected at receiving end at unity power factor but maintaining the same voltage profile. The receiving end voltage if the compensation equipment is not installed will be __________
A
245 kV
B
280 kV
C
255 kV
D
272 kV
An 3 phase alternator star connected 400 V synchronous motor takes a power input of 5472 watts at rated voltage. Its synchronous reactance is 10** per phase and negligible resistance. If its excitation voltage is adjusted equal to the rated voltage of 400 V, its power factor is _______
A
cos(10°)
B
cos(20°)
C
cos(40°)
D
cos(30°)
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the power factor at this operation mode will be _________________
A
0.95
B
0.92
C
0.74
D
0.90
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the power factor angle at this operation mode will be _____________
A
18.04°
B
8.04°
C
21.06°
D
12°
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the power factor at this operation mode will be ____________
A
0.95, lagging
B
0.92, leading
C
0.95, lagging
D
0.90, leading
A single phase 50 hz, generator supplies an inductive load of 5 MW at a power factor of 0.8 lagging using OHTL over 20 km. The resistance and reactance are 0.39Ω and 3.96 Ω. The voltage at receiving station is maintained at 10 KV. The sending end voltage is 11.68 kV. If the voltage regulation is reduced to 50%, then the power factor angle at this operation mode will be ________
A
18.04°, lagging
B
18.04°, leading
C
21.06°, leading
D
21.06°, lagging
If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor
A
become more
B
become less
C
remain constant
D
none of the above