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 : 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 : 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?
Description : A motor which can conveniently be operated at lagging as well as leading power factors is the (A) squirrel cage induction motor. (B) wound rotor induction motor. (C) synchronous motor. (D) DC shunt motor.
Last Answer : (C) synchronous motor.
Description : The drive used in a mixer-grinder is a: (A) dc motor (B) induction motor (C) synchronous motor (D) universal motor
Last Answer : The drive used in a mixer -grinder is a: universal motor
Description : The relative speed between the magnetic fields of stator and rotor under steady state operation is zero for a (A) dc machine. (B) 3 phase induction machine. (C) synchronous machine. (D) single phase induction machine.
Last Answer : Ans: all options are correct
Description : Where can I Buy Rico Mixer Grinder Online in Navi Mumbai?
Last Answer : Buy Rico Mixer Grinder (MG144) online at the best price in Navi Mumbai from A.S Corp. Beautiful ABS plastic body with a heavy-duty 800 watts motor. Shop online now!
Description : What energy change take place in grinder mixer?
Last Answer : electricity to potential energy
Description : Write a paragraph on 'Mixer Grinder'.
Last Answer : Ans: Mixer Grinder is an electronic kitchen appliance that is used to mix and grind various food items. It is compact in size and plays a major role in preparation of food. It usually comes with ... high speed. The high rotation allows the blades to perform all sorts of tasks with utmost efficacy.
Description : A four pole, 60 Hz, three-phase synchronous motor comes up to 1760 RPM when started as an induction motor. What is the percent slip after the rotor field is energized? A. 0 B. 1.1 C. 2.2 D. 3.3
Last Answer : Answer: A
Description : Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under ... A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.
Description : A four-pole 60-hertz induction motor has a synchronous speed of 1800 RPM and a slip of 4 percent at full load. What will be its full load speed? A. 1728.0 RPM B. 1730.7 RPM C. 1800.0 RPM D. 1872.0 RPM
Description : If the synchronous speed of a 12 pole, polyphase, induction motor operating at 60 Hz were 600 RPM, how many poles will be required in a similar motor operating at the same frequency but having a synchronous speed of 900 RPM? A. 4 B. 6 C. 8 D. 18
Last Answer : Answer: C
Description : If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase
Last Answer : Answer: D
Description : The speed of a wound-rotor induction motor _____________. A. will be fixed by the number of field poles B. can be varied by a rheostat-type control C. can only be synchronous speed at full load D. can only attain synchronous speed at no load
Description : The synchronous speed of an induction motor is the ________. A. speed at which the rotor turns B. speed of the rotating field C. frequency of the rotor current D. slip in per cent of rotor RPM
Description : A shaded-pole motor is a ____________. A. synchronous motor B. three-phase induction motor C. compound-wound motor D. single-phase induction motor
Description : A motor using a rheostat in the motor circuit to vary the speed is called a ____________. A. squirrel-cage induction motor B. regenerative braking motor C. wound-rotor induction motor D. synchronous motor
Description : Which of the following statements is true concerning a polyphase synchronous propulsion motor? A. The motor is started as an induction motor. B. Resistance is gradually added to the rotor circuit. C. ... is held below the rated current. D. The field winding is energized for starting purposes only.
Description : Why the induction motor never runs at synchronous speed?
Last Answer : If rotor & stator have same speed, no relative motion {Nr = Ns (1-s)}. Slip is zero, no voltage induce in rotor Current is zero, then torque is zero (T ∞ E2 I2 cos φ2). Thus induction motor never runs at synchronous speed.
Description : The synchronous speed for a 3 phase 6-pole induction motor is 1200 rpm. If the number of poles is now reduced to 4 with the frequency remaining constant, the rotor speed with a slip of 5% will be _________. (A) 1690 rpm (B) 1750 rpm (C) 1500 rpm (D) 1710 rpm
Last Answer : (D) 1710 rpm
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
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
Description : In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction ... armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor
Description : An a.c. tachometer is just a ________with one phase excited from the carrier frequency. (A) two-phase A.C. servomotor (B) two-phase induction motor (C) A.C. operated universal motor (D) hybrid stepper motor.
Last Answer : Ans: D This is a special purpose machine whose stator coil can be energized by electronically switched current.
Description : Why Speed Control of Induction Motor is difficult compared to DC shunt motor?
Last Answer : Answer: Speed Control of DC shunt motor can be possible by providing resistance in the armature and field circuits and varying the resistors speed changes can be carried out over a wide range. ... employed. Care should be taken that in the process efficiency and power factor should be maintained.
Description : The most suitable servomotor for low power applications is (A) a dc series motor. (B) a dc shunt motor. (C) an ac two-phase induction motor. (D) an ac series motor.
Last Answer : (B) a dc shunt motor.
Description : The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator
Description : The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor
Description : Regarding an induction motor, the power developed by the rotor automatically adjusts itself to the _____________. A. power required to drive the load B. speed required to drive the load C. current flow in the motor stator D. torque developed by the rotating field
Description : What are the differences between synchronous and induction motor?*
Last Answer : Synchronous motor : Constant speed on all loads, can be operated on a wide range of power factors, not self starting, requires dc excitation.
Description : The length cf air gap to be provided in ______ is primarily determined by power factor consideration. (a) d.c. series motor . (b) d.c. shunt motor (c) induction motor (d) synchronous motor
Last Answer : (c) induction motor
Description : What will happen if the induction motor runs at synchronous speed ?
Last 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 : Synchronous wattage of induction motor means: A) rotor input in watts B) stator input in watts C) combined stator and rotor input in watts D) shaft output in watts
Last Answer : Synchronous wattage of induction motor means: rotor input in watts
Description : A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because?
Last 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 : Which motor have more efficiency, synchronous motor or induction motor?
Last Answer : Synchronous motor has more efficiency.
Description : The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?
Last Answer : Ns equals f/pair pole 50/4 - 12.5
Description : Induction generator a) can not work in isolation b) can work in isolation c) should work in parallel with synchronous generators d) any of the mentioned
Last Answer : Ans: C
Description : The cycles per second developed by the alternator aboard your vessel is determined by _____________. A. the speed of the engine driving the alternator B. the resistance applied to the field rheostat C. the synchronous speed of induction D. the adjustments made to the voltage regulator
Description : The difference between the synchronous speed of an induction machine and its operating speed (slip) may be correctly expressed _____________. A. as a percent of synchronous speed B. as a decimal fraction of synchronous speed C. directly in revolutions per minute D. as all of the above
Description : Which of the following types of motors is often designed for use in correcting power factor? A. Polyphase B. Wound-rotor C. Induction D. Synchronous
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
Description : Universal motors will operate on AC or DC current, and are generally found in _____________. A. portable tools B. large pump motors C. turbo electric main motors D. forced draft fans
Last Answer : Induction motor is a AC motor it is also known as asynchronous motor .
Description : The synchronous motor which works on leading power factor and does not drive any mechanical load is called?
Last Answer : The synchronous motor which works on leading power factor and does not drive any mechanical load is called synchronous condenser.
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
Description : If a synchronous motor begins to vibrate severely and pull out of synchronism, the cause may be ____________. A. an overload B. an open in the field coils C. no exciter voltage D. all of the above
Description : The speed of a synchronous motor is varied by _____________. A. interchanging any two of the three live leads B. changing the voltage of the system C. changing the input frequency D. increasing the field excitation
Description : What type of electric motor is commonly used to start small auxiliary diesel engines? A. synchronous B. series C. shunt D. cage