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An induction motor has relatively high power factor at near full load.

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Related questions

Description : A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because?

Answer : A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because stator supply is not required to produce magnetic field.

Description : At which time power factor of the induction motor is low?

Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.

Answer : The power factor of a single-phase induction motor is usually lagging.

Answer : For high value of diversity factor, a power station of given installed capacity will be in a position to supply more number of consumers.

Description : Why does induction motor have high starting current?

Answer : In induction motor , the flux produce is quadrature to the applied voltage. Since when we are going to start motor , there is no flux present inside . So in order to lets say compensate it ... times of current to further increase flux. So that is reason for high starting current in induction motor

Description : Power factor of the system is kept high?

Answer : Power factor of the system is kept high to reduce line losses, to maximise the utilization of the capacities of generators, lines and transformers, to reduce voltage regulation of the line.

Description : What is the advantage of high power factor?

Answer : Reduced copper losses Smaller conductor size Improve voltage regulation Increase system capability Less energy bill

Description : Explain energy conservation technique “by improving power quality” for induction motor.

Answer : Energy conservation method in induction motor by improving power quality: Electrical energy can be conserved by improving the power quality. It can be achieved by avoiding voltage unbalance, maintaining ... losses can be minimized by using harmonic filter thus reducing the harmonics in the system.

Answer : High load factor indicates total plant capacity is utilised for most of the time.

Answer : When a D.C. series motor is connected to A.C. supply, the power factor will be low because of high inductance of field and armature circuits.

Description : If the load of the normally excited synchronous motor is increased the power factor will?

Answer : If the load of the normally excited synchronous motor is increased the power factor will become lagging.

Description : The synchronous motor which works on leading power factor and does not drive any mechanical load is called?

Answer : The synchronous motor which works on leading power factor and does not drive any mechanical load is called synchronous condenser.

Description : If the field of synchronous motor is under excited, power factor will be?

Answer : If the field of synchronous motor is under excited, power factor will be lagging.

Description : How can we improve power factor using synchronous motor?

Answer : Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.

Description : An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW

Answer : An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is 83.33 kW

Description : The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?

Answer : Ns         equals        f/pair pole 50/4      - 12.5

Answer : In a distribution system, in order to improve power factor, the synchronous capacitors are installed at the receiving end.

Answer : For a consumer the most economical power factor is generally 0.95 lagging .

Answer : The primary reason for low power factor is supply system is due to installation of induction motors.

Answer : Power plant having maximum demand more than the installed rated capacity will have utilisation factor more than unity.

Answer : Load factor of a power station is generally less than unity.

Answer : Load factor of a power station is defined as average load/maximum demand.

Description : Can a synchronous condenser improve power factor?

Answer : Yes, synchronous condenser can improve power factor.

Description : What is the maximum value of power factor?

Answer : 1 is the maximum value of power factor.

Description : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is (A) 0.2 Ω (B) 0.3 Ω (C) 0.4 Ω (D) 0.5 Ω

Answer : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is 0.3 Ω

Description : Why a dc series motor has a high starting torque?

Answer : Capacitor start motor has high torque in starting

Description : In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.

Description : What will happen if the induction motor runs at synchronous speed ?

Answer : Since there is always slip present in rotor it cannot run at synchronous speed no current will be developed hence no torque will developed

Description : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 

Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent

Description : A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for

Answer : A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for 4 poles

Description : A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60

Answer : 0

Description : The torque developed by any 3-phase induction motor at 0.8 p.u. slip is (A) Full-load torque (B) unstable torque (C) starting torque (D) break down

Answer : The torque developed by any 3-phase induction motor at 0.8 p.u. slip is unstable torque

Description : The number of poles in a phase induction motor at 50 Hz and running at 1500 rpm will be?

Answer : The number of poles in a phase induction motor at 50 Hz and running at 1500 rpm will be 4.

Description : A change of 4% in the supply voltage to an induction motor will produce a change of approximately

Answer : A change of 4% in the supply voltage to an induction motor will produce a change of approximately 8% in the rotor torque

Description : In an induction motor if the flux density is reduced to one-half, of its normal value then the torque will  (1) reduce to one-half (2) reduce to one-fourth (3) remain unchanged (4) increase four times

Answer : In an induction motor if the flux density is reduced.to one-half, of its normal value then the torque will reduce to one-fourth

Answer : The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it helps in reducing the tendency of the rotor teeth to remain under the stator teeth.

Description : Why starter is required for starting an induction motor?

Description : What can cause high amperage on a motor?

Answer : High  amperage  can  result  in  a motor  when the  amount  of  load  increases. when  load  increases  , it  reduces  the  rotor  speed which  increases  the  slip  at  constant  synchronous  speed ... ,  as  a  result  more  current  shall  have  been  drawn  to  maintain  the  additional  load.

Description : A transformer has negative voltage regulation when its load power factor is   (1) Zero (2) Unity (3) Leading (4) Lagging

Answer : Leading

Answer : A power factor meter has one current circuit and two pressure circuits.

Description : The power factor at resonance in R-L- C parallel circuit is?

Answer : since a rlc circuit at resonance behaves like a pure resistive circuit, i.e there is no phase difference between current and voltage, hence the power factor is unity.

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

Answer : For power factor correction, synchronous motors operate at no-load and greatly over-excited fields.

Description : At which power factor alternator is said to be overexcited?

Answer : At leading power factor alternator is said to be overexcited.

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.

Description : What is a high tension power line?

Answer : High tension power line is a high voltage of 115 kv and power line is underground transimissio used by urbun areas

Description : Why high voltage can reduce power loss?

Answer : when voltage has increased due to reduced current flow, thus power loss given by ( I^2R) will be low due to reduced current(I^2) provided that resistance (R) is constant.

Description : Why high voltage is used in power transmission?

Answer : The primary reason that power is transmitted at high voltages is to increase efficiency. ... The lower current that accompanies high voltage transmissionreduces resistance in the conductors aselectricity flows ... This means that thin, light-weight wires can beused in long-distance transmission.

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