DET20033 - THREE PHASE (PART 2)

In a balance three-phase load, each phase has

• An equal amount of power

• One-third of total power

• Two-third of total power

• A power consumption equal to (√3VL) IL

In a three-phase system, when the loads are perfectly balanced, the neutral current is

• Zero

• One-third of maximum

• Two-thirds of maximum

• At maximum

Identify the value of neutral current in a three phase system with balanced loads condition.

• 0 A

• 0.637 A

• 2 A

• √3 A

Power in a Three Phase Circuit = _________.

• 1. P = 3 VPh IPh CosФ

• 2. P = √3 VL IL CosФ

• Both 1 & 2.

• None of The Above

For a star connected three phase AC circuit ______.

• Phase voltage is equal to line voltage and phase current is three times the line current

• Phase voltage is square root three times line voltage and phase current is equal to line current

• Phase voltage is equal to line voltage and line current is equal to phase current

• None of the above

In a three phase, delta connection_________.

• line current is equal to phase current

• Line voltage is equal to phase voltage

• None of the above

• Line voltage and line current is zero

For a star connection network, consuming power of 1.8kW and power factor 0.5, the inductance and resistance of each coil at a supply voltage of 230 Volts, 60 Hz is ______?

• 0.1H, 8 Ohms

• 0.5H, 10 Ohms

• 0.3H, 7.4 Ohms

• 1H, 7 Ohms

For a three-phase delta connected load, fed from a star connected network, the power transferred to the load is _____?

• 3 kW

• 4.7 kW

• 5 kW

• 7 kW

For the below star connected network of equal resistances, if the Wattmeter reading is 5kW and ammeter reading is 25 Amperes, the power factor, resistance and inductance is ________respectively

• 1, 5 Ohms, 0.1H

• 0.866, 8 Ohms, 0.02H

• 0.5, 10 Ohms, 0.01H

• 0.4, 8 Ohms, 0.02H

For a three phase, three wire system, the two Wattmeter read 4000 Watts and 2000 Watts respectively. The power factor when both meters give direct reading is _______ ?

• 1

• 0.5

• 0.866

• 0.6