Last Answer : The speed of a universal motor is usually reduced by using gearing.
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114 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Speed control of a universal motor is achieved by varying field flux with tapped field windings, connecting rheostat in series, applying variable voltage by means of silicon controlled rectifier, applying variable voltage by means of variable auto-transformer.
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100 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The speed control of universal motor used for sewing machines is by varying the resistance.
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105 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The speed of a universal motor is generally reduced by using gear trains.
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96 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.
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164 views
1 answer
asked
Mar 20, 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
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481 views
1 answer
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May 8, 2018
by
anonymous

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.
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142 views
1 answer
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Mar 20, 2018
by
anonymous

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.
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2.7k views
1 answer
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Jul 5, 2019
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anonymous

Last Answer : A universal motor is one which can be operated either on D.C. or A.C. supply at approximately the same speed and output.
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71 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : In a universal motor, the most common cause of brush sparking is open armature winding, shorted armature winding, shorted field winding, high commutator mica.
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147 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.
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248 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : https://youtu.be/fgQTs-1hq7Q
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70 views
1 answer
asked
Mar 19, 2020
by
anonymous

State working principle of universal motor with the help of diagram.
Last Answer : Working Principle of Universal motor : It is modified DC series motor which can work on AC as well as DC supply. According to basic motor principle, whenever a current carrying conductor is placed in magnetic ... They have nearly same operating characteristic for both AC and DC supply.
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145 views
1 answer
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Aug 17, 2019
by
anonymous

applications of each: i) Universal motor ii) Stepper motor.
Last Answer : i) Applications of Universal motor: 1) portable drills 2) hair dryers 3) grinders 4) mixers 5) table-fans 6) blowers 7) polishers 8) Kitchen appliances ii) Applications of Stepper motor ... 7) robotics 8) CNC machine 9) Control systems 10) Biomedical applications 10) XY recorder 11) plotters
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137 views
1 answer
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Aug 17, 2019
by
anonymous

State two applications of 1) Shaded pole motor 2) Universal motor
Last Answer : (i)Applications of Shaded pole motor: 1. Small fans 2. Toy motors 3. Hair dryers 4. Ventilators 5. Electric clocks 6. Record players 7. Motorized valves 8. Gramophones 9. Photocopying ... 5. Portable Drilling Machines 6. Electric Shavers 7. Mechanical computing Machines 8. Machine Tools etc.
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125 views
1 answer
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Jul 26, 2019
by
anonymous
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Draw and explain working of universal motor. Give two applications of universal motor.
Last Answer : Figure of Universal motor: Operation of universal motor on A.C. and D.C. supply: *A universal motor works on either DC or single phase AC supply. When the universal motor is ... , regardless of AC or DC supply, universal motor works on the same principle that DC series motor works.
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361 views
4 answers
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Jul 20, 2019
by
anonymous

Last Answer : A universal motor can run on either A.C. or D.C.
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70 views
1 answer
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Mar 20, 2018
by
anonymous

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.
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111 views
1 answer
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Mar 20, 2018
by
anonymous
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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
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548 views
1 answer
asked
Apr 28, 2018
by
anonymous

In synchronous motor, does the winding losses vary with load?
Last Answer : No, in the synchronous motor the winding losses do not vary with load.
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512 views
1 answer
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Mar 3, 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
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234 views
1 answer
asked
May 1, 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
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151 views
1 answer
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Apr 28, 2018
by
anonymous

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

Last Answer : Series motor has the poorest speed control.
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103 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
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389 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.
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134 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.
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114 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : In a D.C. shunt motor, speed is independent of armature current.
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87 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Centrifugal switch disconnects the auxiliary winding of the motor at about 70 to 80 percent of synchronous speed.
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222 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.
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164 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in damage to the starting winding.
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129 views
1 answer
asked
Mar 20, 2018
by
anonymous

Why the speed of synchronous motor is constant?
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67 views
0 answers
asked
Mar 15, 2018
by
anonymous

What are the speed control methods of dc motor?
Last Answer : Field control of DC motor Armature control of DC motor
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254 views
2 answers
asked
Dec 16, 2017
by
anonymous

speed control methods of three phase induction motor?
Last Answer : Speed control of three phase induction motor
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363 views
2 answers
asked
Aug 9, 2017
by
anonymous
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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
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150 views
1 answer
asked
Apr 28, 2018
by
anonymous

Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
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131 views
0 answers
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Apr 16, 2020
by
anonymous

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.
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158 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : A synchronous motor running with normal excitation adjusts to load increases essentially by increase in armature current.
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195 views
1 answer
asked
Mar 20, 2018
by
anonymous

The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Last 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.
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302 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The coupling angle or load angle of synchronous motor is defined as the angle between the rotor and the stator poles of opposite polarity.
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218 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then the stator current will be zero.
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116 views
1 answer
asked
Mar 20, 2018
by
anonymous

If the load of the normally excited synchronous motor is increased the power factor will?
Last Answer : If the load of the normally excited synchronous motor is increased the power factor will become lagging.
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150 views
1 answer
asked
Mar 18, 2018
by
anonymous

The synchronous motor which works on leading power factor and does not drive any mechanical load is called?
Last Answer : The synchronous motor which works on leading power factor and does not drive any mechanical load is called synchronous condenser.
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162 views
1 answer
asked
Mar 18, 2018
by
anonymous

In a synchronous motor which losses varies with load?
Last Answer : In a synchronous motor, copper losses varies with load.
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102 views
1 answer
asked
Mar 18, 2018
by
anonymous

The synchronous motor will develop maximum power when the load angle is?
Last Answer : The synchronous motor will develop maximum power when the load angle is 900.
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223 views
1 answer
asked
Mar 18, 2018
by
anonymous

Why dc series motor should not be started at no load?
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629 views
0 answers
asked
Mar 15, 2018
by
anonymous

An electric motor in which both stator field and rotor rotates with same speed is called?
Last Answer : An electric motor in which both stator field and rotor rotates with same speed is called synchronous motor.
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177 views
1 answer
asked
Mar 18, 2018
by
anonymous

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.
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270 views
1 answer
asked
Oct 13, 2019
by
anonymous

Last Answer : If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.
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201 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.
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121 views
1 answer
asked
Mar 20, 2018
by
anonymous
