Electrical Axis Quiz - General Category 1

A voltage source of 50 cos1000t is in series with 1 kilo-ohm resistor and 1 micro-Farad capacitor. What is the circuit current in mili-ampere?

• -25 + j25

• -25 - j25

• 25 - j25

• 25 + j25

A balanced wye connected load of 30 + j30 per phase is connected to a 3-phase, 50 Hz 208 Volts supply. Determine the value of each capacitor in mili-Farad which will yield unity power factor?

• 9.63

• 8.29

• 9.28

• 8.84

For the following phase currents Ia= 34.64, Ib= -10 -j17.32, Ic= -10 + j17.32. What is the positive sequence for phase c?

• 12.44 -j21.55

• 12.44 + j21.55

• -12.44 + j21.55

• -12.44 - j21.55

Five resistance of 5, 10, 15, 20 and 25 ohms are connected in parallel. What is the total resistance?

• 0.21898

• 218.98

• 2.1898

• 21.898

A 10 micro-Farad capacitor is charged by a constant current source and its voltage is increased to 2 Volts in 5 seconds. Calculate the value of the constant current source in micro amperes.

• 5

• 6

• 4

• 3

The equipment grounding conductor is required to be in the same metal enclosure as the circuit conductor to protect against____________.

• induced current in metal enclosure

• surge current in metal enclosure

• maintaining constant voltage

• increases impedance of the circuit

An air core toroidal coil has 120 turns and the length is 12 cm. What is the current required to set up a flux of 1.2 x 10 ^-6 weber, if the cross sectional area is 12 sq.cm?

• 0.8419

• 0.7960

• 0.8119

• 0.7718

A circuit has load impedance Z = 50 +j80 ohms. Determine the parallel capacitance in micro-Farad required to correct the power factor to unity?

• 32

• 36

• 24

• 28

A three phase, 13 kV distribution line delivers 8 MVA of load. The per phase impedance of line is 0.01 + j0.05 p.u.

• 650 +j130

• 130 +j650

• 130 - j650

• 650 -j130

A shunt motor with an armature resistace of 0.15 ohms is running 1,200 rpm for a load which requires an armature current of 50 amperes from a 230 V source. At no load, the armature current is 5 amperes. If the effect of armature reaction has reduced the air gap flux 2% from no load to full load, what is the no-load speed?

• 1,213 rpm

• 1,210 rpm

• 1,208 rpm

• 1,212 rpm