# For starting a D.C. motor a starter is required because?

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For starting a D.C. motor a starter is required because it limits the starting current to a safe value.

## Related questions

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Description : Why starter is required for starting an induction motor?

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Last Answer : A direct online starter is used for starting motors up to 5 H.P.

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Last Answer : The starting resistance of a D.C. motor is generally low.

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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

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Description : Which type of starter is used to start the DC motor?

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Description : Why a dc series motor has a high starting torque?

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Description : In a double squirrel cage induction motor, good starting torque is produced as (A) Large current flows through the outer high resistance winding. (B) Large current flows through the inner high ... the outer high resistance winding. (D) Large current flows through the inner low resistance winding.

Last Answer : In a double squirrel cage induction motor, good starting torque is produced as Large current flows through the outer high resistance winding.

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Last Answer : For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.

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Last Answer : The starting winding of a single-phase motor is placed in stator.

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Last Answer : If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.

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Last Answer : Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.

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Description : How is a three phase cage induction motor self starting?

Last Answer : Any type of induction motor is self starting. Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting

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Description : Is induction motor is self starting?

Last Answer : Single phase induction motor is not self starting. Three phase induction motor is self starting.

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Last Answer : Capacitor start motor has high torque in starting

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

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Description : List different starting methods of three phase synchronous motor. Explain any one of them.

Last Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor.

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Last Answer : The value of starting capacitor of a fractional horse power motor will be 300 uF .

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Last Answer : A centrifugal switch is used to disconnect starting winding when motor has picked up about 50 to 70 per cent of rated speed.

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Last Answer : The rotor developed by a single-phase motor at starting is zero.

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Last Answer : In a capacitor start motor, the phase displacement between starting and running winding can be nearly 90°.

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Description : A synchronous motor can be made self starting by providing?

Last Answer : A synchronous motor can be made self-starting by providing damper bar.

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Description : Why does induction motor have high starting current?

Last Answer : In induction motor , the flux produce is quadrature to the applied voltage. Since when we are going to start motor , there is no flux present inside . So in order to lets say compensate it ... times of current to further increase flux. So that is reason for high starting current in induction motor

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Last Answer : At the instant of starting when a D.C. motor is put on supply, it behaves like a low resistance circuit.

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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.

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Last Answer : Three point starter can be used for both shunt and compound motor.

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Last Answer : A three point starter is considered suitable for shunt as well as compound motors.

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Description : What is an auto transformer starter?

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Last Answer : Sparking, is discouraged in a D.C. motor because commutator gets damaged.

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Description : 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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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

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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

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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 :

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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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

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

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Last Answer : If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor.

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

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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

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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.

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

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Last Answer : The armature voltage control of D.C. motor provides constant torque drive.

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

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

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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.

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Last Answer : Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be cumulatively compounded.

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Last Answer : D.C. Series motor is generally preferred for cranes and hoists.

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Last Answer : (b) Clostridium butylicum Lipase Removal of oil stains

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Last Answer : Sparking at the commutator of a D.C. motor may result in damage to commutator segments, damage to commutator insulation, increased power consumption.

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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.

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Last Answer : Cumulatively compounded D.C. motor will be suitable along with flywheel for intermittent light and heavy loads.