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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.

Answer : The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

Description : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu

Answer : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu

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.

Description : The synchronous motor will develop maximum power when the load angle is?

Answer : The synchronous motor will develop maximum power when the load angle is 900.

Answer : Series motor has got maximum self relieving property.

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%.

Description : State maximum power transfer theorem for DC circuit.

Answer : Maximum power transfer theorem for DC circuit: The maximum power transfer theorem states that the source or a network transfers maximum power to load only when the load resistance is equal ... removed (disconnected) ii) All internal independent sources are replaced by their internal resistances.

Description : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of 600 C/W. If the ambient temperature is 300o C ... the device will be A) 1.52 W B) 1.72 W C) 1.92W D) 2.00 W

Answer : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of  ... 300o C, then the maximum allowable power dissipation in the device will be 2.00 W 

Answer : In repulsion motor, maximum torque is developed when brush axis is at 45° electrical to the field axis.

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.

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.

Description : The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as?

Answer : Differentially compounded D.C. motor has got maximum self loading property.

Description : For maximum transfer of power, internal resistance of the source should be?

Answer : For maximum transfer of power, internal resistance of the source should be equal to load resistance.

Description : What is the maximum value of torque angle in synchronous motor?

Answer : The maximum value of torque angle in synchronous motor is 90 degrees electrical.

Description : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?

Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.

Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Description :  An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when A) ZL = R B) ZL = jXS C) ZL = R-jXS D) ZL = R+jXS 

Answer :  An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when ZL = R-jXS

Answer : In a power plant if the maximum demand on the plant is equal to the plant capacity, then plant reserve capacity will be zero.

Description : Maximum Power Transfer Theorem 1

Answer : Maximum Power Transfer Theorem 1

Description : "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with?

Answer : "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with Maximum power transfer theorem.

Answer : Maximum demand on a power plant is the greatest of all "short time interval averaged" demand during a period.

Answer : Power plant having maximum demand more than the installed rated capacity will have utilisation factor more than unity.

Description : The maximum load that a power transformer can carry is limited by its?

Answer : The maximum load that a power transformer can carry is limited by its voltage ratio.

Description : What is the maximum value of power factor?

Answer : 1 is the maximum value of power factor.

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.

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

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

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

Answer : The type of D.C. motor used for shears and punches is cumulative compound D.C. motor.

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

Answer : Cumulative compound D.C. motor is preferred for elevators.

Answer : The power mentioned on the name plate of an electric motor indicates the output power available at the shaft.

Description : How can we improve power factor using synchronous motor?

Answer : Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.

Description : At which time power factor of the induction motor is low?

Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.

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

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?

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.

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.

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

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

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.

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

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

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

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

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

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

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

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

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