1 Answer

Answer :

If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.

Related questions

Description : Why does the speed of a DC shunt motor decrease as the load increases?

Last Answer : Because if the load is increasing then the torque must also be increase. If not then the speed of motor will decrease.

Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.

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

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

Last Answer : In a D.C. shunt motor, speed is independent of armature current.

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.

Last Answer : If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.

Description : If field current is decreased in shunt dc motor, the speed of the motor (a) remains same. (b) increases. (c) decreases. (d) none of the above.

Last Answer : increases

Last Answer : The speed of a D.C. shunt motor more than its full-load speed can be obtained by decreasing the field current.

Description : DC shunt 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%; }

Description : State any four applications of DC shunt motor.

Last Answer : Applications of DC shunt motor: 1) Lathe machines 2) drilling machines 3) milling machines 4) Printing machinery 5) Paper industry 6) centrifugal and reciprocating pumps 7) blowers 8)fans

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

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

Last Answer : For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.

Last Answer : The armature torque of the D.C. shunt motor is proportional to armature current.

Last Answer : In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.

Last Answer : If the field of a D.C. shunt motor gets opened while motor is running the motor will attain dangerously high speed.

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

Last Answer : In a manual shunt motor starter over load relay is connected in series and no volt relay in parallel with the load.

Last Answer : D.C. shunt motors are used for driving machine tools.

Description : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) ... proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α

Last Answer : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ

Description : The speed of a D.C. motor can be controlled by varying  1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above

Last Answer : The speed of a D.C. motor can be controlled by varying  1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.

Description : What are the speed control methods of dc motor?

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

Description : The counter e.m.f. of a d.c. motor?

Last Answer : The counter e.m.f. of a d.c. motor helps in energy conversion.

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.

Last 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.

Last Answer : The purpose of retardation test on D.C. shunt machines is to find out stray losses.

Last Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.

Description : As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit?

Last Answer : As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit a resistance is connected in series with armature.

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.

Description : Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter. 

Last Answer : Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter

Description : State at least one function and the material used for the following parts of DC Motor.

Last Answer : Part Function Material Yoke -Provides mechanical support for poles -Acts as protecting cover for machine -Provides path for magnetic flux Cast Iron OR Cast Steel Field Winding - ... Pole core  Provides mechanical support to field winding. Cast Iron OR Cast Steel

Description : A d.c. motor can be looked upon as d.c. generator with the power flow?

Last Answer : A d.c. motor can be looked upon as d.c. generator with the power flow reversed.

Description : The Eb/V ratio of a d.c. motor is an indication of its?

Last Answer : The Eb/V ratio of a d.c. motor is an indication of its efficiency.

Description : The normal value of the armature resistance of a d.c. motor is?

Last Answer : The normal value of the armature resistance of a d.c. motor is 0.5.

Description : In a d.c. motor, unidirectional torque is produced with the help of

Last Answer : Commutator provides unidirectional torque and pulsating dc

Description : In DC motor iron losses are occurred in?

Last Answer : In DC motor iron losses are occurred in the armature.

Last Answer : Series motor has got maximum self relieving property.

Description : D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the?

Last Answer : D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the compound motor.

Description : D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the?

Last Answer : DC motor mostly preferred is DC series motor becaus the load is continuous for a long time

Last Answer : Shunt motors,  Series motors, Compound motors

Last Answer : Torque developed by a D.C. motor depends upon magnetic field, active length of the conductor, current flow through the conductors, number of conductors, radius of armature.

Last Answer : In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will run as induction motor.

Description : A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?

Last Answer : 200V/E2 = 1000/1200 E2= 240 V

Last Answer : In a differentially compounded D.C. motor, if shunt field suddenly opens the motor will first stop and then run in opposite direction as series motor.

Last Answer : If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses.

Description : The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be?

Last Answer : The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be 580 V.

Description : Speed control of the motor using TRIAC

Last Answer : Speed control of the motor using TRIAC:  This basic phase triggering circuit uses the triac in series with the motor across an AC sinusoidal supply. The variable resistor, VR1 is used ... meaning that it may not trigger at the exact same point for each positive and negative half cycle.

Description : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Last Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases 

Description : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm

Last Answer : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm