89 views
what is separately excited motor ?

1 Answer

Answer :

the field winding have different source power supply and armature have different power supply source
Like 0 like

Please log in or register to answer this question.

Related questions

362 views

Description : Separately Excited DC motor

Last Answer : Separately Excited DC motor

2 answers
125 views

Description : separately excited dc motor controlled by chopper with a frequency of 500hz and source voltage of 230v and rated value of motor is 220v 24A 100 rpm find its duty ratio at 1.2 times rated torgue and 500rpm

0 answers
1.4k views

Description : A separately excited d.c. motor fed from single phase full converter with firing angle 60° runs at 1000 r.p.m. If motor is connected to single phase semiconverter with the same firing angle of 60°, it would run at (a) 2000 rpm (b) 1850 rpm (c) 1500 rpm (d) 1000 rpm 

Last Answer : Ans =1500

3 answers
1.1k views

Description : A single-phase half-controlled rectifier is driving a separately excited dc motor. The dc motor has a back emf constant of 0.5 V/rpm. The armature current is 5 A without any ripple. The armature resistance is 2 Ohm. The ... of the motor will be  (A) 339 rpm (B) 359 rpm (C) 366 rpm (D) 386 rpm

Last Answer : 359

1 answer
461 views

Description : A DC chopper is used for regenerative braking of a separately excited DC motor. The DC supply voltage is 400V. The armature current during regenerative braking is kept constant at 300 A with negligible ripple. For a duty cycle of 60% ... to the DC supply is  (a) 78 kW (b) 58 kW (c) 38 kW (d) 48 kW

Last Answer : 48

2 answers
235 views

Description : A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor :  (A) can be operated in first quadrant (B) ... in first & second quadrants (C) can be operated in first & fourth quadrants (D) cannot be operated

Last Answer : A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor : can be operated in first & fourth quadrants

1 answer
158 views

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

1 answer
1.2k views

Description : A separately excited dc motor is required to be controlled, from a 3-phase supply, for its operation in the first quadrant only. The most preferred converter would be  (a) 3-phase fully controlled ... converter with free wheel diode (c) 3-phase dual converter (d) 3-phase half wave converter 

Last Answer : A

1 answer
9 views

Description : What is the difference between self-excited and separately excited DC generator? 

Last Answer : Self-excited generator: In a self-excited generator the field winding is excited by an external DC source like a battery etc. Separately excited generator: In a separately excited generator the field poles ... is again fed to the field winding and goes on till the generator builds up voltage. 

1 answer
15 views

Description : A separately excited generator as compared to a self-excited generator (a) is amenable to better voltage con-trol (b) is more stable (c) has exciting current independent of load current (d) has all above features

Last Answer : Ans: d

1 answer
341 views

Description : A separately excited d.c. machine is coupled to a 50 Hz, three-phase, 4-pole induction machine as shown in the figure. The Dc machine is energized first and the machines rotate at 1 600 ... three phase source, the phase sequence being consistent with the direction of rotation. In steady state

Last Answer : A separately excited d.c. machine is coupled to a 50 Hz, three-phase, 4-pole induction machine as shown in the figure. The Dc machine is energized first and the machines rotate at 1 600 1pm. ... rotation. In steady state DC machine acts as a motor and the induction machine acts as a generator  

1 answer
95 views

Description : The supply both to field and armature circuits are disconnected simultaneously in a separately excited dc motor and it comes to a standstill in 5 sec. If the armature circuit of this motor is disconnected from supply with field ... rest in (1) 5 sec (2) 7 sec (3) 4 sec (4) A very long time  

Last Answer : 5 sec only.standstill time doesn't depend upon field excitation

1 answer
107 views

Description : A separately excited dc generator is running at rated speed and at no load. If its field winding is suddenly connected to a dc source then rise in armature generated voltage is governed by (1) Armature time constant (2) Field time constant (3) Both (a) and (b) (4) Mechanical time constant

0 answers
140 views

Last Answer : In a separately excited generator supplying rated load the armature reaction is always present.

1 answer
128 views

Last Answer : A separately excited generator as compared to a self-excited generator is amenable to better voltage control, more stable, has exciting current independent of load current.

1 answer
1 view

Description : The basic type of D.C. motor speed control where a generator armature directly feeds the motor armature and the motor and generator fields are excited by a separate D.C. source is called ___________________. A. Burmeister-Wain B. Ward-Leonard C. Sperry-Rand D. Atlas-Copco

Last Answer : Answer: B

1 answer
12 views

Description : On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above this are obtained by _____________. A. rotating brush ... B. raising the generator engine speed C. lowering the generator engine speed D. decreasing excitation

Last Answer : Answer: B

1 answer
82 views

Description : An a.c. tachometer is just a ________with one phase excited from the carrier frequency. (A) two-phase A.C. servomotor (B) two-phase induction motor (C) A.C. operated universal motor (D) hybrid stepper motor.

Last Answer : Ans: D This is a special purpose machine whose stator coil can be energized by electronically switched current.

1 answer
219 views

Description : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the ... frequency of induced voltage across slip ring is A) 30 Hz B) 70 Hz C) 20 Hz D) 35 Hz

Last Answer : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is 70 Hz

1 answer
1.3k views

Description : A single-phase induction motor with only the main winding excited would exhibit the following response at synchronous speed  (A) Rotor current is zero (B) Rotor current is non-zero and is ... and backward rotating fields are equal (D) Forward rotating field is more than the backward rotating field

Last Answer : A single-phase induction motor with only the main winding excited would exhibit the following response at synchronous speed  (A) Rotor current is zero (B) Rotor current is non-zero and is ... backward rotating fields are equal (D) Forward rotating field is more than the backward rotating field

1 answer
134 views

Description : A 0.5 Hp, 6 pole wound rotor induction motor is excited by a 3 phase 60 Hz source. Calculate the frequency of the rotor current at standstill.  (A) 50 Hz (B) 30 Hz (C) 60 Hz (D) 120 Hz 

0 answers
79 views

Last Answer : An over excited synchronous motor on noload is known as synchronous condenser.

1 answer
158 views

Description : 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.

1 answer
507 views

Description : If the field of synchronous motor is under excited, power factor will be?

Last Answer : If the field of synchronous motor is under excited, power factor will be lagging.

1 answer
109 views

Last Answer : Self excited Dc motor have same source of power to armature and field winding

1 answer
304 views

Description : The heating time constant of a totally enclosed motor is relatively Select one: a. higher b. lower c. independent of type of enclosure. d. small .

Last Answer : B

1 answer
188 views

Description : The efficiency of a 3-phase, star connected synchronous motor is 95% and it takes 24A at full load and unity power factor. What will be the induced e.m.f. if total mechanical power developed at full load and 0.9 power factor leading is 14620W. The synchronous impedance per phase is (0.2+j2) Ω.

0 answers
245 views

Description : 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.

1 answer
146 views

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

1 answer
74 views

Description : Which motor is generally used in Tap Recorders? A) universal motor B) reluctance motor C) split phase motor D) hysteresis motor

Last Answer : Which motor is generally used in Tap Recorders? A) universal motor B) reluctance motor C) split phase motor D) hysteresis motor

1 answer
77 views

Description : A 200 V dc motor takes a field current of 2 A to generate a back emf of 180 V. If the field winding resistance is 80 Ω, the resistance of the shunt field regulator is (A) 10 Ω (B) 20 Ω (C) 100 Ω (D) 180 Ω

0 answers
69 views

Description : As the speed increases, the torque developed by a dc servo motor (A) decrease with a negative slope (B) increases with a positive slope (C) remain constant (D) becomes unstable 

0 answers
62 views

Description : The starting torque of a V/f controlled inverter-fed 3-phase induction motor operating at 25 Hz as compared with the same motor operating at 50 Hz is (A) more (B) double (C) equal (D) less 

0 answers
64 views

Description : Regenerative breaking of ac-dc converter fed dc motor is possible when firing delay angle of SCRs is (A) 30° (B) 60° (C ) 90° (D) 120°

0 answers
70 views

Description : In slip-energy recovery scheme of converter-fed 3-phase induction motor, super synchronous speeds are possible by (A) injecting voltage into the stator (B) injecting voltage into the rotor (C) extracting voltage from the stator (D) extracting voltage from the rotor. 

0 answers
74 views

Description : Fast acceleration and high-speed cruising electric traction drive motor is (A) separately excited dc motor (B) DC series motor (C) AC series motor (D) 3-phase squirrel cage induction motor 

0 answers
149 views

Description :  As compared to a split phase motor, a capacitor start motor has _____.

Last Answer :  As compared to a split phase motor, a capacitor start motor has higher starting torque.

1 answer
142 views

Description : For very low speed and high power applications the best suited ac motor is:

Last Answer : For very low speed and high power applications the best suited ac motor is: synchronous motor

1 answer
1.2k views

Description : If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: (1) 50% of the previous value (2) 25% of the previous value (3) 150% of the previous value (4) 125% of the previous value

Last Answer : If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: 25% of the previous value

1 answer
507 views

Description : For a 1.8o, 2-phase bipolar stepper motor, the stepping rate is 100 steps/second. The rotational speed of the motor in rpm is  (A) 15 (B) 30 (C) 60 (D) 90

Last Answer : For a 1.8o, 2-phase bipolar stepper motor, the stepping rate is 100 steps/second. The rotational speed of the motor in rpm is 30 

1 answer
515 views

Description : The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 ... .5 A from the same source will be  (A) 48.0% (B) 57.1% (C) 59.2% (D) 88.8%

Last Answer : The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 48.0%

1 answer
308 views

Description : The following motor definitely has a permanent magnet rotor  (A) DC commutator motor (B) Brushless dc motor (C) Stepper motor (D) Reluctance motor

Last Answer : The following motor definitely has a permanent magnet rotor Stepper motor

1 answer
375 views

Description : A 400 V, 50 Hz 30 hp, three-phase induction motor is drawing 50 A current at 0.8 power factor lagging. The stator and rotor copper losses are 1.5 kW and 900 W respectively. The friction and windage losses are 1050 W and the ... the motor will be (A) 23.06 kW (B) 24.11 kW (C) 25.01 kW (D) 26.21 kW

Last Answer : A 400 V, 50 Hz 30 hp, three-phase induction motor is drawing 50 A current at 0.8 power factor lagging. The stator and rotor copper losses are 1.5 kW and 900 W respectively. The friction and windage losses are 1050 W and the core losses are 1200 W. The air-gap power of the motor will be 25.01 kW

1 answer
760 views

Description : In a stepper motor, the detent torque means  (A) minimum of the static torque with the phase winding excited (B) maximum of the static torque with the phase winding excited (C) minimum of ... torque with the phase winding unexcited (D) maximum of the static torque with the phase winding unexcited

Last Answer : In a stepper motor, the detent torque means maximum of the static torque with the phase winding unexcited

1 answer
463 views

Description : The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor ... Hz supply is  (A) 58.5 A (B) 45.0 A (C) 42.7 A (D) 55.6 A

Last Answer : The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 , V 57 Hz supply is 45.0 A 

1 answer
206 views

Description : In case of split phase motor, the phase shift between currents in the two windings is around  A) 30° B) 70° C) 90° D) 120°

Last Answer : In case of split phase motor, the phase shift between currents in the two windings is around  30°

1 answer
185 views

Description : Which type of motor is most suitable for computerprinter drive?  A) Reluctance motor B) Hysteresis motor C) Shaded pole motor D) Stepper motor

Last Answer : Stepper motor type of motor is most suitable for computer printer drive?.

1 answer
597 views

Description : The torque speed characteristic of a repulsion motor resembles which of the following d.c. motor characteristics  A) Separately excited B) Shunt C) Series D) Compound

Last Answer : The torque speed characteristic of a repulsion motor resembles which of the following d.c. motor characteristics Series 

1 answer
176 views

Description : In a Synchronous motor, the magnitude of stator back e.m.f (Eb) depends on

Last Answer : In a Synchronous motor, the magnitude of stator back e.m.f (Eb) depends on DC excitation only

1 answer
...