How does the degree of DC excitation affect pull-out torque?

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Description : The purpose of a cage rotor winding placed on the rotor of a synchronous motor is to _____________. A. provide excitation to the DC field B. start the machine as an induction motor C. contribute extra torque at synchronous speed D. prevent the machine from falling out of step

Last Answer : Answer: B

Description : In a diesel electric plant, raising the generator's field excitation will cause the DC propulsion motor to ________. A. increase in speed B. decrease in speed C. affect generator speed only D. affect main motor speed if done in conjunction with higher generator engine speeds

Last Answer : Answer: A

Description : A damper winding is designed as part of a synchronous motor to ____________. A. increase efficiency B. provide starting torque C. provide excitation D. eliminate slippage

Last Answer : Answer: B

Description : The function of amortisseur, or damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Last Answer : Answer: C

Description : The function of damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Last Answer : Answer: C

Description : Electric propulsion coupling excitation is reduced at slow speeds to ___________. A. increase speed control B. increase shaft torque C. prevent coupling overheating D. prevent coupling slippage

Last Answer : Answer: C

Description : The voltage developed by an AC generator is controlled by varying the ____________. A. speed of the prime mover B. AC excitation to the field C. DC excitation to the field D. DC excitation of the voltage regulator

Last Answer : Answer: C

Description : The most common source of excitation for synchronous motors is a/an ______________. A. stepup transformer B. half-wave rectifier C. DC supply D. AC supply

Last Answer : Answer: C

Description : The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator

Last Answer : Answer: B

Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Last Answer : Answer: C

Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

Description : On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above this are obtained by _____________. A. rotating brush ... B. raising the generator engine speed C. lowering the generator engine speed D. decreasing excitation

Last Answer : Answer: B

Description : A hysteresis motor (A) is not a self-starting motor. (B) is a constant speed motor. (C) needs dc excitation. (D) can not be run in reverse speed.

Last Answer : (B) is a constant speed motor

Description : What is pull out torque?

Last Answer : The maximum torque developed by the motor without pulling out of synchronism is called pull out torque. Its value varies from 1.5 to 3.5 times full load torque.

Description : What is pull in torque?

Last Answer : The torque which is required to pull the motor into synchronism when it is running as induction motor is called pull in torque.

Description : Rated speed of an engine is the speed at which an engine devlopes (A) Maximum crankshaft torque (B) Maximum brake horse power output (C) Maximum thermal efficiency (D) Maximum drawback pull

Last Answer : (B) Maximum brake horse power output

Description : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?

Last Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.

Description : A single degree of freedom spring-mass system is subjected to a harmonic force of constant amplitude. For an excitation frequency of √3k/m , the ratio of the amplitude of steady state response to the static deflection of the spring is __________ A. 0.2 B. 0.5 C. 0.8 D. None of the above

Last Answer : B. 0.5

Description : An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. ... between the armature and the bus D. cause high currents to be induced in the field windings

Last Answer : Answer: D

Description : How does increase in excitation of the Alternator connected to infinite bus-bars affect this operation?

Last Answer : Increase in excitation level of the synchronous generator will effectively increase the reactive power supplied by the generator keeping steam input constant.

Description : If we change the excitation of synchronous machine will it affect on power factor?

Last Answer : Yes, If we change the excitation of synchronous machine it will affect on power factor. If the synchronous motor is overexcited then it will have leading power factor and if the motor is underexcited then it will have lagging power factor.

Description : If we change the excitation of synchronous machine will it affect on motor speed?

Last Answer : No, If we change the excitation of synchronous machine it will not affect on motor speed.

Description : The torque produced by a DC motor armature is the product of the force acting at the armature surface multiplied by _____________. A. work done by the armature in one revolution B. effective ... arm at the center of rotation of the armature D. perpendicular distance to its center of rotation

Last Answer : Answer: D

Description : Which of the following operating characteristics for DC motors is considered to give high starting torque? A. series B. shunt C. cumulative-compound D. differential-compound

Last Answer : Answer: A

Description : What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

Last Answer : Answer: B

Description : An across-the-line starter is typically used for which of the following applications? A. Reduced-current starting of large motors B. Low torque starting of small motors C. Low resistance starting of DC motors D. Full-voltage starting of motors

Last Answer : Answer: D

Description : Which motor has high Starting Torque and Staring current DC motor, Induction motor or Synchronous motor?

Last Answer : DC Series motor has high starting torque. We can not start the Induction motor and Synchronous motors on load, but can not start the DC series motor without load.

Description : Which Motor Has High Starting Torque And Staring Current Dc Motor, Induction Motor Or Synchronous Motor?

Last Answer : DC Series motor has high starting torque. We can not start the Induction motor and Synchronous motors on load, but can not start the DC series motor without load.

Description : A dc cumulatively compounded motor delivers rated load torque at rated speed. If series field is short circuited, then the armature current and speed will a) Both increases b) Both decreases c) Increases and decreases d) Decreases and increases

Last Answer : Ans: Both increases

Description : As compared to shunt and compound DC motors, the series DC motor will have the highest torque because of its comparatively ____________ at the start. (A) Lower armature resistance. (B) Stronger series field. (C) Fewer series turns. (D) Larger armature current.

Last Answer : (D) Larger armature current.

Description : The torque, in a _____________is proportional to the square of the armature current (A) DC shunt motor (B) stepper motor (C) 2-phase servomotor (D) DC series motor

Last Answer : (D) DC series motor

Description : The speed-torque characteristics of a DC series motor are approximately similar to those of the _________motor. (A) universal (B) synchronous (C) DC shunt (D) two-phase

Last Answer : Ans: A Universal motor has same characteristics as DC series motor and also known as an a.c series motor.

Description : DC motor gross torque example

Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Description :  A DC Motor develops a torque of 150 N-m. A 10 percent reduction in the field flux causes a 50 percent increase in armature current. The new value of torque is: A) 102.5 N-m B) 202.5 N-m C) 172.5 N-m D) 232.5 N-m

Last Answer : T1=KIf,T2=K1.5I*0.9f T1=150Nm.  T2=T1*1.5*0.9=150*1.35=202.5Nm

Description : In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is :

Last Answer : In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is : 0.075

Description : The dc motor used for intermittent high torque loads is  (1) dc series motor (2) dc shunt motor (3) differential compound motor (4) cumulative compound motor

Last Answer : 4 cumulative compound motor

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

Last Answer : motor

Description : If Earth increases its mass, how would that affect the gravitational pull a person experiences on Earth?

Last Answer : The gravitation pull will increase relative to the amount of increased mass.The Mass of the Objects The more mass two objects have, the greaterthe force of gravity the masses exert on each other. If one of the massesis doubled, the force of gravity between the objects is doubled.

Description : A variable shunt, connected across the series field coils of a DC compound wound generator, to permit adjustment of the degree of compounding, is called a _____________. A. divider B. diverter C. converter D. rheostat

Last Answer : Answer: B

Description : On AC vessels, which of the following statements represents the most difficult problem involved in obtaining a DC potential suitable for use by computer components? A. A stepdown transformer is ... voltage must be rectified and made ripple free. D. Rectifiers cannot operate with voltage regulators.

Last Answer : Answer: C

Description : Why the Led Glow in Dc Supply ? Whenever give the Ac Supply What is Affect in Led ?

Last Answer : LEDs consume DC current to produce light; with AC current the LED will only be lit when current flow is in the proper direction. AC applied to an LED will cause it to blink on and off, and at high frequency the LED will appear to be lit continuously.

Description : A loss of field excitation to an AC generator while operating in parallel will cause it to ____________. A. absorb more and more load due to decreased armature reaction B. lose its load due to ... polarity D. lose its load, begin to motorize, trip out on reverse power relay, and possibly overspeed

Last Answer : Answer: D

Description : The effect of carrying field excitation excessively high on a synchronous motor will result in a _____________. A. tendency for the motor to fall out of step B. tendency for the motor to overspeed C. tendency for the motor to overheat D. loss of motor speed regulation

Last Answer : Answer: C

Description : If first ionisation potential of a hypothetical atom is `16 V`, then the first excitation potential will be :

Last Answer : If first ionisation potential of a hypothetical atom is `16 V`, then the first excitation potential will be : A. `10*2 eV` B. 12 eV C. 14 eV D. 16 eV

Description : a. The P wave represent the electrical excitation of the_____ b. The QRS complex represents the ____ of the ventricles. c. The end of T wave marks the

Last Answer : a. The P wave represent the electrical excitation of the_____ b. The QRS complex represents the ____ of ... The end of T wave marks the end of _____

Description : a. The P wave represent the electrical excitation of the_____ b. The QRS complex represents the ____ of the ventricles. c. The end of T wave marks the

Last Answer : a. The P wave represent the electrical excitation of the_____ b. The QRS complex represents the ____ of ... The end of T wave marks the end of _____

Description : A hydrogen atom in a state of binding energy 0.85 eV makes a transition to a state of excitation energy of 10.2 eV . Find the energy and wavelength of

Last Answer : A hydrogen atom in a state of binding energy 0.85 eV makes a transition to a state of ... . Find the energy and wavelength of photon emitted.

Description : What components compose the excitation current of a transformer. How are they modeled in the transformer's equivalent circuit?

Last Answer : Excitation current Io = Iw + Iu

Description : What components compose the excitation current of a transformer. How are they modeled in the transformer's equivalent circuit?

Last Answer : Excitation current Io = Iw + Iu