AC CIRCUITS

In a balanced 3 phase WYE connected circuit the line voltages are equal __________.

• And so are the line currents

• To the phase voltages

• But the line currents are unequal

• But the phase voltages are unequal

The type of AC distribution system commonly used to supply both light and power is the __________.

• Three phase data

• Three phase WYE system with neutral wire

• Three phase WYE system without neutral

• Open data system

The phase displacement between phasors in polyphase system is always __________.

• 180 degrees

• 360 degrees divided by the number of phases

• 120 degrees

• 90 degrees

In a balanced, 3 phase, WYE connected system the line voltage is __________.

• The phasor difference of the two phase voltages

• 1.414 times the phase voltage

• 0.707 times the phase voltage

• The phasor sum of the two phase voltages

In a WYE connected system, line current is __________.

• 1.414 times the phase current

• 1.732 times the phase current

• Equal to the phase current

• 0.707 times the phase current

The advantage of WYE connection over delta connection for same phase voltage is that it gives __________.

• Extra step up voltage

• Extra step up power

• Step down current

• Extra step up current

In a delta connected system, the line current is __________.

• 1.414 times the phase current

• phasor sum of the two phase currents

• 1.732 times the phase current

• Equal to the phase current

Power in WYE connected system is __________.

• Three times the delta system

• Equal to that of delta system

• 1.732 times the delta system

• 1.414 times the delta system

For an unbalanced 3 phase load, which connection is suitable?

• 4 wire, WYE connection

• 3 wire, open delta connection

• 3 wire, WYE connection

• 3 wire, delta connection

What is the minimum number of wattmeters required for measuring power of a three phase balanced load?

• Four

• Three

• Two

• One