# A balanced 3-phase system consists of?

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A balanced 3-phase system consists of positive sequence currents.

## Related Questions

The line current in a balanced delta system is 30 A. The load current is (A) 30√3 A (B) 30/√3 A (C) 10 A (D) 30/√2 A
Last Answer : The line current in a balanced delta system is 30 A. The load current is 30/√3 A

The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero
Last Answer : The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components

A balanced three phase Delta connected load consists of three resistances each of four ohm's connected to a 400 V 3 phase 50 Hz supply. Find 1) phase voltage, 2) phase current, 3) line current, 4) power consumed.

At a particular instant, the R-phase voltage of a balanced 3-phase system is + 30 V, and the Y-phase voltage is – 90 V. The voltage of B-phase at that instant is (A) + 120 V (B) – 120 V (C) – 60 V (D) + 60 V
Last Answer : At a particular instant, the R-phase voltage of a balanced 3-phase system is + 30 V, and the Y-phase voltage is – 90 V. The voltage of B-phase at that instant is + 60 V

Last Answer : Balanced 3 phase Load: Balanced three phase load is defined as star or delta connection of three equal impedances having equal real parts and equal imaginary parts. It takes same current of equal magnitude and equal phase angle.

Define balanced and unbalanced load in three phase circuit.
Last Answer : Balanced Load: When all the imedances of 3 phases are equal in magnitude and of same nature then load is said to be balanced.  Unbalanced Load: When all the imedances of 3 phases are not equal in magnitude and of different nature then load is said to be unbalanced.

A balanced Delta connected load supplied with 440 V 50 Hz three phase AC supply has R=10 Ohm and L=0.6 mH in is each arm. Calculate line and phase current, active power.

A balanced three phase star connected load is supplied from a three phase 400V 50 Hz supply. The resistance for per phase is 10 Ohm. Find the value of phase current, line current, power factor and total power consumed.

Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is
Last Answer : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is constant

What is a balanced diet?
Last Answer : A healthy lifestyle and proper nutrition can not only improve your well-being, but also prevent the development of serious diseases. Today, the number of people suffering from obesity, angina attacks ... lower blood cholesterol levels, as well as minerals and vitamins, including vitamins B6 and E.

Define for polyphase circuit (i) Balanced load (ii) Unbalanced load. Draw one example circuit for each type of load.
Last Answer : i) Balanced Load: Balanced three phase load is defined as star or delta connection of three equal impedances having equal real parts and equal imaginary parts.  Example circuit:  ii) ... satisfy the condition of balance, then it is called as unbalanced load.  Example circuit:

Define balanced supply and unbalanced supply.

The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is (A) zero (B) 0.5 (C) between zero and 0.5 (D) between 0.5 and unity
Last Answer : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is between 0.5 and unity

Define phase sequence of three phase supply with waveforms. What is normal phase sequence? Which 3 standard colours are used to denote the phase sequence?
Last Answer : It  is  sunnosoidal  sequence.

Which of the following 3-phase connection of a transformer causes interference with the neighbouring communication lines:  (A) Delta-Star (B) Star-Delta (C) Delta-Delta (D) Star-Star
Last Answer : Which of the following 3-phase connection of a transformer causes interference with the neighbouring communication lines: Star-Star

A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is :
Last Answer : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is : 200 V

Two 3-phase transformers cannot be operated in parallel, if their :  (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different
Last Answer : Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different

Damper winding is provided in 3 phase synchronous motors to :
Last Answer : Damper winding is provided in 3 phase synchronous motors to : provide starting torque and prevent hunting

The direction of rotation of an inverter fed 3-phase ac motor is reversed by (A) a mechanical reversing switch (B) reversing the input dc link voltage (C) operating the inverter as a rectifier (D) changing the sequence of switching
Last Answer : The direction of rotation of an inverter fed 3-phase ac motor is reversed by changing the sequence of switching

The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm
Last Answer : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm

In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell
Last Answer : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in voltage notching

Last Answer : In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at 120°.

In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are ______ respectively.  (A) positive, negative and negative (B) positive, zero and negative (C) positive, positive and negative (D) positive, negative and zero
Last Answer : In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are positive, negative and negative respectively.

A lightening arrester connected between the line and earth in a power system  (1) protects the terminal equipment against travelling surges (2) protects the transmission line against direct ... suppresses high frequency oscillations in the line (4) reflects back the travelling wave approaching it
Last Answer : A lightening arrester connected between the line and earth in a power system protects the terminal equipment against travelling surges

For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is
Last Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25

With fault clearing time, the transient stability of a power system
Last Answer : With fault clearing time, the transient stability of a power system decreases

Last Answer : In a single bus-bar system there will be complete shut down when fault occurs on the bus itself.

Last Answer : The steady state stability of the power system can be increased by connecting lines in parallel.

Last Answer : Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.

Last Answer : Ungrounded neutral transmission system is not recommended because of system insulation being overstressed due to over voltages, insulation overstress may lead to failure and subsequent phase to phase faults, being inadequately protected against ground fault.

Last Answer : The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to extinguish the arc.

Draw the phasor diagram for Star connected balanced system.

Is it possible for a soil to consist only of one phase?

Explain following techniques related to energy conservation in transmission and distribution system. (i) By balancing phase currents (ii) Variable technical losses (I2R losses).
Last Answer : (i) Balancing Phase currents: Proper (healthy balanced) three phase loads always draw equal currents in all lines but single phase loads in the 3 phase 4 wire system or loads connected between two ... . 11) Minimize I2R losses. 12) Balance the load currents. 13) Regulate the system voltages.

Write short notes on 3 phase AC system.

Phase margin is the amount of angle to make the system  (1) Oscillatory (2) Stable (3) Unstable (4) Exponential
Last Answer : Phase margin is the amount of angle to make the system Unstable

A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm
Last Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm

When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is (A) 86.6% (B) 50% (C) 57.7% (D) 73.2%
Last Answer : When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is 73.2%

write short notes on single phase system.
Last Answer : A "phase" in an electrical system is often referred to as the waveform (may be voltage or the current) of the power supply. The waveform in an AC system is typically ... domestic household or commercial supplies and street lighting. Industrial supplies requires three phase electrical supply .

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What is line voltage and phase voltage? Draw balanced three phase star connected system. Show all the voltages and currents.

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Write short note on UPS and its usage in railway system.
Last Answer : Ans. Ideally, the voltage supply by the utility system should be perfect sine wave without any harmonics, at its nominal frequency of 50 Hz and at its nominal magnitude. In practice however voltage can ... load from one source to the other results in the least amount of disturbance seen by the load.

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Consider a system with seven processes A through G and six resources R through W. Resource ownership is as follows: process A holds nothing and wants R & W process B holds W but wants T process C holds ... V process F holds R and wants S process G holds V and wants U Is the system deadlocked ?

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