In case of conductively compensated D.C. series motors, the compensating winding is provided?
Last Answer : In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.
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1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : When two D.C. series motors are connected in parallel, the resultant speed is normal speed.
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379 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Shunt motors, Series motors, Compound motors
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100 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : D.C. shunt motors are used for driving machine tools.
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85 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The D.C. motors preferred for traction applications beacuse the speed is inversely proportional to the torque and the torque is proportional to square of armature current.
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159 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to improve power factor.
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712 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Regenerative method of braking is based on that back e.m.f. is equal to the applied voltage.
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102 views
1 answer
asked
Mar 20, 2018
by
anonymous

Why are DC motors used in trains and not AC motors ?
Last Answer : The reason is torque. torque is inversely proportional to speed..i.e when th knowe train comes to rest position to motion.. initial speed is zero..so it requires high starting torque for ... current will flow through field and armature coils then maximum torque is available at the intial condition.
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161 views
1 answer
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Sep 3, 2019
by
anonymous

Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
Last Answer : Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
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179 views
1 answer
asked
Apr 29, 2018
by
anonymous

Last Answer : In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.
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250 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.
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145 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.
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120 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Differentially compound D.C. motors can find applications requiring low starting torque.
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125 views
1 answer
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Mar 20, 2018
by
anonymous

A rheostat differs from potentiometer in the respect that it?
Last Answer : A rheostat differs from potentiometer in the respect that it has higher wattage rating.
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84 views
1 answer
asked
Mar 25, 2018
by
anonymous

what is Rheostat ?
Last Answer : Rheostat is varible resistance device which gives large range variation in resistance generally used for operating electrical motors
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76 views
2 answers
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Aug 6, 2017
by
anonymous

Is phenol formaldehyde resin(RESIONOL EPF 87120) suitable for brake liners/Braking applications
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0 answers

Explain in brief how anti-lock braking system works
Last Answer : An ABS is a system on motor vehicles which prevents the wheels from locking while braking stopping safely is one of the most important functions a motor vehicle can perform. Diagram: ... to decrease the pressure on the braking circuit, effectively reducing the braking force on that wheel.
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96 views
1 answer
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Aug 9, 2019
by
anonymous

Last Answer : The braking retardation is usually in the range 10 to 15 km phps.
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245 views
1 answer
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Mar 22, 2018
by
anonymous

Last Answer : Plugging method of braking is generally used in elevators.
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66 views
1 answer
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Mar 20, 2018
by
anonymous

State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.
Last Answer : Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows: 1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine
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381 views
1 answer
asked
May 7, 2020
by
anonymous

Brake test on DC series motor
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%; }
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298 views
2 answers
asked
Apr 21, 2020
by
anonymous

Describe the reason of using dc series motor for electric trains.
Last Answer : Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains
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142 views
1 answer
asked
Sep 18, 2018
by
anonymous

We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be
Last Answer : We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be 2.4 kOhm
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151 views
1 answer
asked
May 8, 2018
by
anonymous

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
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109 views
1 answer
asked
Apr 29, 2018
by
anonymous

A DC voltage source is connected across a series RLC circuit. Under steady-state conditions, the applied DC voltage drops entirely across the
Last Answer : A DC voltage source is connected across a series RLC circuit. Under steady-state conditions, the applied DC voltage drops entirely across the C only
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2.0k views
1 answer
asked
Apr 29, 2018
by
anonymous

Last Answer : If equalising bar is connected to the 2 DC generators the current will be equal in 2 generators irrespective of parallel connection so that we connect equaliser bar
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166 views
2 answers
asked
Mar 21, 2018
by
anonymous

Last Answer : In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to 25% of the previous value.
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503 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.
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114 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : A D.C. series motor is that which has its field winding consisting of thick wire and less turns.
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82 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The direction of rotation of a D.C. series motor can be changed by interchanging field terminals.
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187 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : A.C. series motor as compared to D.C. series motor has smaller brush width, less number of field turns, more number of armature turns, less air gap.
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136 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : If a D.C. series motor is operated on A.C. supply, it will spark excessively, have poor efficiency, have poor power factor.
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91 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last 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.
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119 views
1 answer
asked
Mar 20, 2018
by
anonymous

What are the advantages of DC series motor?
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92 views
0 answers
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Mar 15, 2018
by
anonymous

Why dc series motor should not be started at no load?
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629 views
0 answers
asked
Mar 15, 2018
by
anonymous

Why a dc series motor has a high starting torque?
Last Answer : motor
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86 views
1 answer
asked
Mar 15, 2018
by
anonymous

SYNCHRONOUS MOTORS MCQ
Last Answer : 101. In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then (a) the motor is said to be fully loaded (b) the torque ... square of the applied voltage (c) inversely proportional to applied voltage (d) none of the above Ans: a
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3 answers
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SINGLE PHASE INDUCTION MOTORS MCQ
Last Answer : 101. After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on (a) running winding (b) rotor winding (c) field winding (d) compensating winding Ans: a ... motor is usually reduced by using (a) gearing (b) belts (c) brakes (d) chains Ans: a
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23 views
3 answers

THREE PHASE INDUCTION MOTORS MCQ
Last Answer : 101. Insertion of resistance in the stator of an induction motor (a) increases the load torque (b) decreases the starting torque (c) increases the starting torque (d) none of the above Ans: b
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327 views
3 answers

Suggest electric motors for i) traction ii) crane iii) lathe machine iv) domestic fan.
Last Answer : i) Traction :- DC Series motor ii) Crane :- DC Series motor iii) Lathe machine :- 3 phase Induction motor or DC shunt motor iv) Domestic fan :- 1 phase induction motor
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75 views
1 answer
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Aug 17, 2019
by
anonymous
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State which electric motors are generally used in electro agro systems with reason.
Last Answer : 1) 3 phase induction motor is used in electro agro system for water pumping from wells as 3 phase ac supply is easily available, cost of induction motor is less, maintenance free being rugged ... as 1 phase ac supply is easily available for domestic purpose, repair is simple and easily available.
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95 views
1 answer
asked
Aug 17, 2019
by
anonymous

State factors for selection of motors as drive.
Last Answer : Following Factors governing / or are considered while selecting electric drive (Motor) for particular application: Factors to be considered for selection of Electrical Drives: 1) Nature of Supply:- ... level, load equalization 7) Cost: - Capital, Running and maintenance cost should be less.
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1.9k views
2 answers
asked
Aug 17, 2019
by
anonymous

Compare variable reluctance and permanent magnet motors.
Last Answer : Variable reluctance Motor Permanent magnet motors The rotor is not magnetised The rotor is magnetised High torque to inertia ratio Low torque to inertia ratio ... rotor has salient pole construction The rotor has mostly smooth cylindrical type of construction.
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2.5k views
1 answer
asked
Jul 30, 2019
by
anonymous

What are the factors to be considered while selection of motors for different drives?
Last Answer : Following Factors are considered while selecting electric drive (Motor) for particular application: Factors to be considered for selection of Electrical Drives: 1) Nature of Supply:- Whether supply ... , load equalization 7) Cost: - Capital, Running and maintenance cost should be less.
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143 views
1 answer
asked
Jul 30, 2019
by
anonymous

3 phase motor 42 hp same ratting two motors but pole change 2 and 4 pole tell me difference amp of both motors
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2.6k views
0 answers
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Jul 24, 2019
by
ZAHID

A relay used for protection of motors against overload is : (A) Impedance relay (B) Electromagnetic attraction type (C) Thermal relay (D) Buchholz's relay
Last Answer : D
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548 views
2 answers
asked
May 8, 2018
by
anonymous

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
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93 views
1 answer
asked
Apr 29, 2018
by
anonymous

Stepper motors are used in (1) printers (2) lifts (3) amplifiers (4) oscillators
Last Answer : Stepper motors are used in printers
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69 views
1 answer
asked
Apr 29, 2018
by
anonymous

Slot harmonics are reduced in induction motors by using (A) fractional-pitch windings (B) fractional-slot windings (C) integral-slot windings (D) distributed windings
Last Answer : Slot harmonics are reduced in induction motors by using fractional-slot windings
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79 views
1 answer
asked
Apr 28, 2018
by
anonymous

Generally, Crawling in squirrel cage induction motors is tendency to run stably at speeds as low as (A) One-third of their synchronous speed (B) One-fifth of their synchronous speed (C) One-seventh of their synchronous speed (D) One-ninth of their synchronous speed
Last Answer : Generally, Crawling in squirrel cage induction motors is tendency to run stably at speeds as low as One-seventh of their synchronous speed
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102 views
1 answer
asked
Apr 28, 2018
by
anonymous
