IEE1-(AC Circuits Part 2)

• A

• B

• C

• D

In a balanced three-phase Y-connected system, the line voltage and the corresponding phase voltage are displaced from each other by

• 0°

• 30°

• 90°

• 120°

• A

• B

• C

• D

Three 10-ohm resistors connected in wye are supplied from a balanced three phase source where phase a line voltage is given by 230 sin377t. What is the phase a line current?

• 13.28 sin377t

• 23 sin (377t-30°)

• 13.28 sin(377t -30°)

• 40 sin(377t + 30°)

A wye-connected, three phase system has the following sequence components of current

Zero sequence current = 12.5 cis 30°

Positive sequence current = 28 cis (-45°)

Negative sequence current = 20 cis (-32°)

Determine the current flowing in the neutral wire

• 4.17 cis 30°

• 37.5 cis 30°

• 35.7 cis (-60°)

• 22.5 cis 10°

• A

• B

• C

• D

One conductor of a three-phase line is open. The current flowing to the delta-connected load through line a is 20 A With the current in line a as reference and assuming that line c is open, what is the negative sequence current of phase a?

• 10+ j5.78

• 10-j5.78

• j11.55

• -10 + j5.78

A balanced delta load of 3 + j4 ohms per phase is connected to a balanced 110 v source Find the line

current

• 22 A

• 38.1 A

• 11 A

• 19.05 A

A balanced three-phase 4,157 v rms source supplies a balanced three-phase delta-connected load of 38.4 +j28.8 ohms. Find the current in line A with V_an as reference

• 120-j90 A

• 120 + j90 A

• -120 + j90 A

• -120-j90 A

• A

• B

• C

• D