# what are the types of dc motor?

what are the types of dc motor?

145 views

1.Separately excited dc motors

2.self excited dc motors

self excited dc motors are further classified into

a)dc series motor b) dc shunt motor c)dc compound motor -

in compound motors there are two types i.cummulative compound dc motor ii.diffirential compound dc motor

## Related Questions

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

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

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

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°

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 ... .5 A from the same source will be  (A) 48.0% (B) 57.1% (C) 59.2% (D) 88.8%
Last 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%

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
Last 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

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
Last 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

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

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
Last Answer : The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque

What is the RPM of a DC motor?

What are the speed control methods of dc motor?
Last Answer : Field control of DC motor Armature control of DC motor

Last Answer : Induction motor is a AC motor it is also known as asynchronous motor .

Armature control of DC motor
Last Answer : Armature control of DC motor

Field control of DC motor
Last Answer : Field control of DC motor

Separately Excited DC motor
Last Answer : Separately Excited DC motor

Four Quadrant Operation Of DC Motor

Types of three phase induction motor rotor
Last 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.

In a 6-pole wave wound dc machine the number of conductors is 70. The back pitch and commutator segments, respectively, are (A) 11and 35 (B) 12 and 34 (C) 13 and 35 (D) 14 and 34

The number of brushes in a 6-pole double-layer lap wound dc machine is (A) 8 (B) 6 (C) 4 (D) 2

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
Last 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

The demagnetizing AT/pole of a 4-pole dc generator is 480. The number of conductors is 480 and the current in each conductor is 40 A. Then the required brush shift in mechanical degrees (A) 9° (B) 7° (C) 5° (D) 3°

In a dc shunt generator critical field circuit resistance line is the line drawn (A) above the OCC (B) below the OCC (C) tangent to the saturation curve (D) tangent to the linear portion of OCC

A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is
Last Answer : A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.87

A 36 slot, 4 -pole, dc machine has a simplex lap winding with two conductors per slot. The back pitch and front pitch adopted could be respectively
Last Answer : A 36 slot, 4 -pole, dc machine has a simplex lap winding with two conductors per slot. The back pitch and front pitch adopted could be respectively 19,17

The fall in speed of a dc generator due to increase in load can be corrected by  (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover
Last Answer : It   can  be  corrected  by  increasing  the  input  to  the  prime  mover.

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

Identify the increasing order of voltage regulation of the following dc generators a same load :  (A) differential compound, shunt and under compound  (B) shunt, differential compound and ... C) under compound, shunt and differential compound  (D) shunt, under compound and differential compound
Last Answer : Identify the increasing order of voltage regulation of the following dc generators a same load : under compound, shunt and differential compound

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.  ... winding, to create a pole of opposite polarity as the main pole ahead in the direction of rotation.
Last 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.

The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is  (1) 1000V (2) 100V (3) 600V (4) 10,000V
Last Answer : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V

Aluminium is not used as winding wire for the armature of a dc machine because  (1) aluminium has low resistivity (2) a large winding space is taken by aluminium conductors and creates ... ) the thermal conductivity of aluminium is low (4) aluminium has low conductivity as compared to copper
Last Answer : Aluminium is not used as winding wire for the armature of a dc machine because  (2) a large winding space is taken by aluminium conductors and creates jointing problems (3) the thermal conductivity of aluminium is low (4) aluminium has low conductivity as compared to copper

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
Last Answer : In a dc machine, interpoles are used to neutralize the effect of armature reaction in the interpolar region

What is the difference between an AC and DC generator?
Last 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.

What is the principle of DC generator?

Brushes of DC machine are made up of ?
Last Answer : Brushes of DC machine are made up of carbon.

From which material field coils of DC generator are made of?
Last Answer : Field coils of DC generator are usually made of copper.

Why is the armature of DC generator laminated?
Last Answer : The armature of DC generator is laminated to reduce eddy current losses.

In DC generators lamination core are generally made of?
Last Answer : In DC generators lamination core are generally made of silicon steel.

Last Answer : Ac motor required AC power supply while DC motor required DC power supply.  AC motor do not have commutator and DC motor have commutator.  Speed of Ac motor can be varied by ... or three phase but DC motor can only be single phase.

The heating time constant of a totally enclosed motor is relatively Select one: a. higher b. lower c. independent of type of enclosure. d. small .

The efficiency of a 3-phase, star connected synchronous motor is 95% and it takes 24A at full load and unity power factor. What will be the induced e.m.f. if total mechanical power developed at full load and 0.9 power factor leading is 14620W. The synchronous impedance per phase is (0.2+j2) Ω.

Split phase induction motor
Last Answer : Split phase induction motor : There are two windings used in split phase induction motor. It is a type of single-phase induction motor. There are two winding one is called main winding and ... motor have low starting torque it is used for small fans, blowers, centrifugal pumps, grinders etc.

Which motor is generally used in Tap Recorders? A) universal motor B) reluctance motor C) split phase motor D) hysteresis motor
Last Answer : Which motor is generally used in Tap Recorders? A) universal motor B) reluctance motor C) split phase motor D) hysteresis motor

The starting torque of a V/f controlled inverter-fed 3-phase induction motor operating at 25 Hz as compared with the same motor operating at 50 Hz is (A) more (B) double (C) equal (D) less

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.

Fast acceleration and high-speed cruising electric traction drive motor is (A) separately excited dc motor (B) DC series motor (C) AC series motor (D) 3-phase squirrel cage induction motor

As compared to a split phase motor, a capacitor start motor has _____.
Last Answer :  As compared to a split phase motor, a capacitor start motor has higher starting torque.

For very low speed and high power applications the best suited ac motor is:
Last Answer : For very low speed and high power applications the best suited ac motor is: synchronous motor

If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: (1) 50% of the previous value (2) 25% of the previous value (3) 150% of the previous value (4) 125% of the previous value
Last Answer : If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: 25% of the previous value

For a 1.8o, 2-phase bipolar stepper motor, the stepping rate is 100 steps/second. The rotational speed of the motor in rpm is  (A) 15 (B) 30 (C) 60 (D) 90
Last Answer : For a 1.8o, 2-phase bipolar stepper motor, the stepping rate is 100 steps/second. The rotational speed of the motor in rpm is 30