3 phase circuits

In a 3-phase system, each phase separates by __ with respect to other phases

• 60

• 120

• 360

• 180

Answer explanation

How are phases arranged in a 3 phase system?

In a 3-phase system, the load is shared across three power wires. The three power wires (A,B and C) are arranged to be out of phase with each other. All three phases of power have entered the cycle by 120⁰. By doing this, the three phases of power peak in voltage at different times during a complete cycle.

For the same output power rating, three phase motor size will be ___ than a single phase motor

• Smaller

• Larger

When the three phase load connected to a three phase star supply system is Balenced, then current (Amps) flowing through the neutral conductor will be

• Positive

• Negitive

• Zero

Answer explanation

The neutral wire serves as a return path for electrical current while the ground wire provides a path for electrical current to earth

For the same amount of electrical power to be delivered, losses in single phase system will be less compared to losses in three phase system:

T/F

• True

• False

3-Phase Induction Motor has the advantage of Low Cost, Less Maintenance and Rugged Construction

T/F

• True

• False

Starting Currents of 3-Phase Induction Motor is about ____ times of the full load current

• 2-3

• 10-20

• 5-7

• half

Crawling occurs in Induction Motor due to which of the following

• harmonics develop

• overload

• low supply voltage

Which of the following 3-Phase induction Motor requires external resistor circuit in rotor during starting of the motor,

https://www.youtube.com/watch?v=JPn5Ou-N0b0

• Slip-Ring Induction Motor

• Squirrel Cage Induction Motor

Which of the following supply is given to the rotor winding of 3-Phase Induction Motor

• AC

• DC

• No Supply goes to the rotor

• Pulsating Supply

3-Phase Induction motor will have ____ power factor during no load condition

• Low

• High

• Moderate