How can we increase the induced current?
Last Answer : Induced current can be increased by reducing no of windings on the secondary part compared to primary.
Show More
91 views
1 answer
asked
Mar 14, 2018
by
anonymous

Why does increase in current mean a decrease in voltage?
Last Answer : This is because current flows from high potential to low potential to bring the two diffrent potential to unity , thus a reduced potential (voltage)
Show More
166 views
1 answer
asked
Mar 10, 2018
by
anonymous

Last Answer : The size of a synchronous motor decreases with the increase in flux density.
Show More
196 views
1 answer
asked
Mar 20, 2018
by
anonymous

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
Show More
342 views
1 answer
asked
May 3, 2018
by
anonymous
.jpg)
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.
Show More
375 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Locked rotor current of a shaded pole motor is slightly more than full load current.
Show More
85 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a synchronous motor, the armature current has large values for high and low excitation.
Show More
142 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The armature current of the synchronous motor has large values for low and high excitation.
Show More
107 views
1 answer
asked
Mar 20, 2018
by
anonymous

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
Show More
143 views
2 answers
asked
Mar 15, 2018
by
anonymous

How to Increase Gas Mileage
Last Answer : How to Increase Gas Mileage Gasoline is a top priority in the budget of any car owner. You'll be surprised at how much you spend on gasoline in between refills, especially if you drive every day. With ... , but also save big money on trips to the fuel pump and refills for your car's fuel tank.
Show More
7 views
1 answer
asked
May 11, 2021
by
anonymous

How to Increase Fiber in Your Diet ?
Last Answer : How to Increase Fiber in Your Diet Increasing fiber in your diet has many health benefits. Fiber is shown to lower cholesterol levels, lower the chances of getting type 2 diabetes, decrease the possibility ... of eight to ten glasses of water daily. The water helps your body digest the fiber faster.
Show More
8 views
1 answer
asked
May 9, 2021
by
anonymous

Reduction in core losses and increase in permeability are obtained with transformer employing?
Last Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.
Show More
615 views
1 answer
asked
Mar 19, 2018
by
anonymous

For given applied voltage, with the increase in frequency of the applied voltage?
Last Answer : For given applied voltage, with the increase in frequency of the applied voltage eddy current loss will remain unchanged.
Show More
241 views
1 answer
asked
Mar 19, 2018
by
anonymous

What are three ways you can increase the strength of an electromagnet?
Show More
77 views
0 answers
asked
Mar 14, 2018
by
anonymous

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.
Show More
426 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The current drawn by the armature of D.C. motor is directly proportional to the torque required.
Show More
585 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last 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.
Show More
507 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The direction of rotation of universal motor can be reversed the by reversing the flow of current through either armature winding or field winding.
Show More
258 views
1 answer
asked
Mar 20, 2018
by
anonymous

The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents
Last Answer : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only
Show More
196 views
1 answer
asked
Apr 29, 2018
by
anonymous

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.
Show More
233 views
1 answer
asked
Sep 20, 2018
by
anonymous

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
Show More
142 views
1 answer
asked
Sep 18, 2018
by
anonymous

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
Show More
487 views
1 answer
asked
May 8, 2018
by
anonymous

Damper winding in a synchronous motor
Last Answer : Damper winding in a synchronous motor Serves to start the motor.
Show More
87 views
1 answer
asked
May 8, 2018
by
anonymous

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.
Show More
137 views
1 answer
asked
May 8, 2018
by
anonymous

A change of 4% in the supply voltage to an induction motor will produce a change of approximately
Last Answer : A change of 4% in the supply voltage to an induction motor will produce a change of approximately 8% in the rotor torque
Show More
491 views
1 answer
asked
May 8, 2018
by
anonymous

In an induction motor if the flux density is reduced to one-half, of its normal value then the torque will (1) reduce to one-half (2) reduce to one-fourth (3) remain unchanged (4) increase four times
Last Answer : In an induction motor if the flux density is reduced.to one-half, of its normal value then the torque will reduce to one-fourth
Show More
374 views
1 answer
asked
May 1, 2018
by
anonymous

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
Show More
238 views
1 answer
asked
May 1, 2018
by
anonymous

The number of poles of 8/6 stepper motor can be :
Last Answer : The number of poles of 8/6 stepper motor can be : 4
Show More
280 views
1 answer
asked
Apr 30, 2018
by
anonymous

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
Show More
112 views
1 answer
asked
Apr 29, 2018
by
anonymous

For using regenerative breaking, the most suitable motor is : (A) DC series motor (B) Slip ring induction motor (C) Squirrel cage induction motor (D) Synchronous motor
Last Answer : For using regenerative breaking, the most suitable motor is : Slip ring induction motor
Show More
93 views
1 answer
asked
Apr 29, 2018
by
anonymous

Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be
Last Answer : Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be 25 N -m
Show More
431 views
1 answer
asked
Apr 29, 2018
by
anonymous

The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is
Last Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent
Show More
363 views
1 answer
asked
Apr 29, 2018
by
anonymous

A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for
Last Answer : A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for 4 poles
Show More
311 views
1 answer
asked
Apr 29, 2018
by
anonymous

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
Show More
2.5k views
1 answer
asked
Apr 29, 2018
by
anonymous

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
Show More
156 views
1 answer
asked
Apr 28, 2018
by
anonymous

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 ... (C) both windings develop the same starting torque (D) both windings develop high starting current
Last 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
Show More
107 views
1 answer
asked
Apr 28, 2018
by
anonymous

In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in ... increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor
Last Answer : In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then the flux first decreases and then increases in the same direction
Show More
95 views
1 answer
asked
Apr 28, 2018
by
anonymous

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
Last 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
Show More
100 views
1 answer
asked
Apr 28, 2018
by
anonymous

The effect of increasing load on a synchronous motor running with normal excitation is (A) Increase both its Ia and power factor. (B) Decrease Ia, but increase power factor. (C) Increase Ia, but decrease power factor (D) Decrease both Ia and power factor.
Last Answer : The effect of increasing load on a synchronous motor running with normal excitation is Increase Ia, but decrease power factor
Show More
569 views
1 answer
asked
Apr 28, 2018
by
anonymous

A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60
Last Answer : 0
Show More
2.1k views
2 answers
asked
Apr 28, 2018
by
anonymous

An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW
Last Answer : An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is 83.33 kW
Show More
179 views
1 answer
asked
Apr 28, 2018
by
anonymous

The torque developed by any 3-phase induction motor at 0.8 p.u. slip is (A) Full-load torque (B) unstable torque (C) starting torque (D) break down
Last Answer : The torque developed by any 3-phase induction motor at 0.8 p.u. slip is unstable torque
Show More
3.1k views
1 answer
asked
Apr 28, 2018
by
anonymous

In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is (A) 0.2 Ω (B) 0.3 Ω (C) 0.4 Ω (D) 0.5 Ω
Last Answer : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is 0.3 Ω
Show More
169 views
1 answer
asked
Apr 28, 2018
by
anonymous

A three-phase synchronous motor connected to ac mains is running at full load and unity power factor. lf its shaft load is reduced by half and field current is held constant then its new power factor will be
Last Answer : Leading
Show More
567 views
2 answers
asked
Apr 28, 2018
by
anonymous

Last Answer : In variable speed motor a weaker commutating field is needed at low speed than at high speed.
Show More
64 views
1 answer
asked
Mar 20, 2018
by
anonymous

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.
Show More
99 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Series motor has the poorest speed control.
Show More
103 views
1 answer
asked
Mar 20, 2018
by
anonymous
.jpg)
Last Answer : For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.
Show More
168 views
1 answer
asked
Mar 20, 2018
by
anonymous

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
Show More
397 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : At the instant of starting when a D.C. motor is put on supply, it behaves like a low resistance circuit.
Show More
132 views
1 answer
asked
Mar 20, 2018
by
anonymous
.jpg)