Description : What are the speed control methods of dc motor?
Answer :
Field control of DC motor Armature control of DC motor
asked
Dec 16, 2017
by
anonymous
Description : What is the RPM of a DC motor?
asked
Mar 15, 2018
by
anonymous
Description : Describe the reason of using dc series motor for electric trains.
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
asked
Sep 18, 2018
by
anonymous
Description : A 200 V dc motor takes a field current of 2 A to generate a back emf of 180 V. If the field winding resistance is 80 Ω, the resistance of the shunt field regulator is (A) 10 Ω (B) 20 Ω (C) 100 Ω (D) 180 Ω
asked
Jun 4, 2018
by
anonymous
Description : As the speed increases, the torque developed by a dc servo motor (A) decrease with a negative slope (B) increases with a positive slope (C) remain constant (D) becomes unstable
asked
Jun 4, 2018
by
anonymous
Description : Regenerative breaking of ac-dc converter fed dc motor is possible when firing delay angle of SCRs is (A) 30° (B) 60° (C ) 90° (D) 120°
asked
Jun 4, 2018
by
anonymous
Description : The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be (A) 48.0% (B) 57.1% (C) 59.2% (D) 88.8%
Answer :
The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 48.0%
asked
May 17, 2018
by
anonymous
Description : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be
Answer :
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be 474 V
asked
May 8, 2018
by
anonymous
Description : A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is
Answer :
A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is 36 Ohm
asked
May 3, 2018
by
anonymous
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 :
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
asked
Apr 29, 2018
by
anonymous
Description : The function of a brush and commutator arrangement in a dc motor is to (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking
Answer :
The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque
asked
Apr 29, 2018
by
anonymous
Answer :
Induction motor is a AC motor it is also known as asynchronous motor .
asked
Sep 9, 2017
by
anonymous
Description : Armature control of DC motor
Answer :
Armature control of DC motor
Description : Field control of DC motor
Answer :
Field control of DC motor
Description : Separately Excited DC motor
Answer :
Separately Excited DC motor
Description : Four Quadrant Operation Of DC Motor
Answer :
Four Quadrant Operation Of DC Motor
Description : Types of three phase induction motor rotor
Answer :
Types of three phase induction motor rotorSquirrel cage rotor : There are two types of three phase induction motor rotor one is squirrel cage rotor and second is wound rotor. About 80 to ... control of three phase induction motor via rotor resistance control method is possible with this rotor.
Description : What are the five types of single phase motors used in the industry?
asked
Mar 15, 2018
by
anonymous
Answer :
Dc machine is classified as self excited separately excited permanent magnet Self excited Dc motor is further classified as series ... are classified as long shunt short shunt
asked
Sep 18, 2017
by
anonymous
Description : What are the parts of AC motor?
asked
Mar 15, 2018
by
anonymous
Description : What are the advantages of DC series motor?
asked
Mar 15, 2018
by
anonymous
Description : Equalizer rings are used in a dc machine to (A) provide mechanical balance (B) balance the flux produced by the poles (C) provide path for the circulating currents (D) overcome armature reaction
Answer :
Equaliser rings in dc machine is Current flowing in machines to share equally during parcel operation of dc machines In case of Equaliser rings are not connected to machine the load ... between two machines flowing not equally Equaliser rings are use series and compound motors only
asked
Jun 4, 2018
by
anonymous
Description : In dc machines, the armature windings are placed on the rotor because of the necessity for (1) electromechanical energy conversion (2) generation of voltage (3) commutation (4) development of torque
Answer :
3 Commutation
asked
May 1, 2018
by
anonymous
Description : In a DC generator the windings of interpoles are connected : (A) in series with main field winding, to create a pole,of same polarity as the main pole ahead in the direction of rotation. (B) in series with main field winding, to create a pole of opposite polarity as the main pole ahead in the direction of ... in the direction of rotation. (D) in series with the armature winding, to create a pole of opposite polarity as the main pole ahead in the direction of rotation.
Answer :
In a DC generator the windings of interpoles are connected : in series with the armature winding, to create a pole of same polarity as the main pole ahead in the direction of rotation.
asked
Apr 29, 2018
by
anonymous
Description : In a dc machine, interpoles are used to (1) neutralize the effect of armature reaction in the interpolar region (2) generate more induced emf in the armature (3) avoid interference of the armature flux with the main -field flux (4) reduce the demagnetizing effect of armature reaction
Answer :
In a dc machine, interpoles are used to neutralize the effect of armature reaction in the interpolar region
asked
Apr 29, 2018
by
anonymous
Description : Brushes of DC machine are made up of ?
Answer :
Brushes of DC machine are made up of carbon.
asked
Mar 3, 2018
by
anonymous
Description : From which material field coils of DC generator are made of?
Answer :
Field coils of DC generator are usually made of copper.
asked
Mar 3, 2018
by
anonymous
Description : In DC generators lamination core are generally made of?
Answer :
In DC generators lamination core are generally made of silicon steel.
asked
Mar 3, 2018
by
anonymous
Description : What is the difference between an AC and DC generator?
Answer :
The generator which generates DC voltage is called DC generator and generator which generates AC voltage is called AC generator (or) Alternator. In DC generator armature is rotated and field winding ... generator. A DC generator can generate low voltages but an AC generator can generate upto 11kv.
asked
Mar 15, 2018
by
anonymous
Description : What is the principle of DC generator?
asked
Mar 15, 2018
by
anonymous
Description : In slip-energy recovery scheme of converter-fed 3-phase induction motor, super synchronous speeds are possible by (A) injecting voltage into the stator (B) injecting voltage into the rotor (C) extracting voltage from the stator (D) extracting voltage from the rotor.
asked
Jun 4, 2018
by
anonymous
Description : In a split-phase induction motor, the resistance/reactance ratios of windings are such that (A) current in the auxiliary winding leads the current in the main winding (B) current in the auxiliary winding lags the current in the main winding (C) both windings develop the same starting torque (D) both windings develop high starting current
Answer :
In a split-phase induction motor, the resistance/reactance ratios of windings are such that current in the auxiliary winding leads the current in the main winding
asked
Apr 28, 2018
by
anonymous
Answer :
In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will remain unchanged.
asked
Mar 20, 2018
by
anonymous
Answer :
In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be less than 50%.
asked
Mar 20, 2018
by
anonymous
Answer :
In a A.C. series motor armature coils are usually connected to commutator through resistance.
asked
Mar 20, 2018
by
anonymous
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.
asked
Mar 20, 2018
by
anonymous
Description : If the load current and flux of a DC motor are held constant, and voltage applied across its armature is increased by 10%, its speed will: (A) Decrease by 10%. (B) Remain unchanged. (C) Increase by 10%. (D) Increase by 20%.
asked
Apr 5, 2018
by
anonymous
Description : In DC motor iron losses are occurred in?
Answer :
In DC motor iron losses are occurred in the armature.
asked
Mar 26, 2018
by
anonymous
Answer :
The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.
asked
Mar 20, 2018
by
anonymous
Answer :
Centrifugal switch disconnects the auxiliary winding of the motor at about 70 to 80 percent of synchronous speed.
asked
Mar 20, 2018
by
anonymous
Description : What is the definition of induction motor?
Answer :
its working on magnetic base made by coils and its work with 1 phase or 3 phase ac or dc supply
asked
Mar 17, 2018
by
anonymous
Description : What is the function of induction motor?
Answer :
while you give supply to motor its motor run on magnet base
asked
Mar 17, 2018
by
anonymous
Description : What will happen if you increase the current in the motor?
Answer :
Increasing current means increasing frequency of the motor because current is directly proportional to rotations of the motor rotor
asked
Mar 15, 2018
by
anonymous
Description : What is the principle of synchronous motor?
asked
Mar 15, 2018
by
anonymous
Description : What is the use of synchronous motor?
asked
Mar 15, 2018
by
anonymous
Description : What is the principle of AC motor?
asked
Mar 15, 2018
by
anonymous
Description : What is mean by plugging in three phase induction motor?
Answer :
Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.
asked
Mar 3, 2018
by
anonymous
Description : what is a pony motor ?
Answer :
pony motor is a small induction motor
Description : what is separately excited motor ?
Answer :
the field winding have different source power supply and armature have different power supply source
Answer :
AC motor AC motor have two types one is Induction motor and second is synchronous motor. Induction motor have two types one is single phase induction motor and second is three phase ... self starting motor so using external motor or we have to start it as induction motor.