Professional Electrical Engineering Quiz 3 PART 2

A 50 MW coal-fired power plant has an average heat rate of 11,000 BTU/kWHR. Coal has a heating value of 13,000 BTU per pound. The plant has a load factor of 80%. How much coal is burned per day?

• 8.1 x 10⁵ lb

• 8.1 x 10⁶ lb

• 1.2 x 10⁶ lb

• 7.2 x 10⁵ lb

Three identical resistors are connected in wye across 220 V, 3-phase lines. The line current is 12.7 A. To what value in volts should the line voltage be changed to obtain the same line current with the resistors connected in delta?

• 98.6

• 132.8

• 120

• 73.3

A sinusoidal current having peak value of 7.07 A is superimposed on DC of 5 A. If a hot-wire ammeter is used to measure the combined current in the circuit, it will indicate ____ amperes.

• 7.07

• 10

• 12.07

• 2.07

A 4-way switch controls a lamp from ____ different locations.

• 1

• 2

• 3

• 4

When a V-V system is converted into a Δ-Δ system, increase in the capacity of the system is ____ percent.

• 86.5

• 73.2

• 66.6

• 50

A small wind generator is designed to generate 50 kW of power at a wind velocity of 25 miles per hour. What is the approximate blade diameter?

• 9.98 m

• 12.98 m

• 11.98 m

• 10.98 m

A synchronous generator having a subtransient reactance of 0.15 pu and operating at 5 percent above its rated voltage supplies a synchronous motor having a 0.20 pu subtransient reactance. The motor is connected to the generator by a transmission line and a transformer of total reactance 0.305 pu. A sudden three-phase fault occurs at the generator terminals. Determine the per unit subtransient fault current.

• -j7.079 pu

• -j8.079 pu

• -j9.079 pu

• -j10.079 pu

The capacitance between any two conductors of a three-phase, three-conductor cable is 2 µF. The cable operates at 11 kV line voltage and 50 Hz. What is the charging current through the cable capacitance?

• 7.98 A

• 4 A

• 6.93 A

• 12 A

A meter has a full-scale current of 50 µA, what is its sensitivity?

• 20 kΩ/V

• 20 V/kΩ

• 50 kΩ/V

• 50 µA/V

The current-carrying capacity of a copper wire having twice the diameter of another copper wire is ____ as great.

• Twice

• Half

• 4 times

• 3 times