What is the back EMF in Transformers?

Question

asked Mar 15, 2018 by anonymous

59 views

Please log in or register to answer this question.

← Prev Question Next Question →

Related questions

asked Mar 15, 2018 by anonymous

What is back EMF in inductor?

0 like 0 dislike

126 views 0 answers

asked Mar 15, 2018 by anonymous

What is the back EMF of a dc motor?

0 like 0 dislike

2.5k views 0 answers

asked Mar 15, 2018 by anonymous

What is the back EMF of the motor?

0 like 0 dislike

50 views 0 answers

asked Mar 15, 2018 by anonymous

What is the back EMF?

Last answer: When the armature of a d.c. motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence e.m.f. is induced in them as in a generator. The ... that energy conversion in a d.c. motor is only possible due to the production of back emf.

0 like 0 dislike

66 views 1 answer

asked Apr 27, 2020 by anonymous

What is back emf?

Last answer: Back EMF: When a current carrying conductor is placed in a magnetic field it experiences a force; when it moves due to the force it (conductor) cuts the magnetic field due to which an emf is ... (hence the applied armature voltage) is opposed by the induced emf which is therefore called as Back emf.

0 like 1 dislike

61 views 1 answer

asked Mar 15, 2018 by anonymous

What is back EMF of synchronous motor?

0 like 0 dislike

59 views 0 answers

asked Mar 15, 2018 by anonymous

Do AC induction motors have back EMF?

0 like 0 dislike

52 views 0 answers

asked Mar 18, 2018 by anonymous

The back emf of synchronous motor depends on?

Last answer: The back emf of synchronous motor depends on load angle.

0 like 0 dislike

47 views 1 answer

asked Mar 20, 2018 by anonymous

What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?

Last answer: The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.

0 like 0 dislike

374 views 1 answer

asked Mar 20, 2018 by anonymous

In case of D.C. shunt motors the speed is dependent on back e.m.f. only because?

Last answer: In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

0 like 0 dislike

145 views 1 answer

asked Mar 20, 2018 by anonymous

The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is?

Last 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.

0 like 0 dislike

144 views 1 answer

asked Sep 7, 2018 by anonymous

What is Phase sequence? Draw waveforms of 3 phase emf.

Last answer: Phase sequence: It is the order in which the three phases reach their peak or maximum values. It is shown in below fig. the phase sequence is A-B-C (or R-Y-B). In the following waveforms, it is ... 120º, B- phase voltage attains its positive maximum value. So the phase sequence is R-Y-B.

0 like 0 dislike

67 views 1 answer

asked Jan 15, 2018 by James

of what use are current and voltage transformers in protective systems

Last answer: Current transformers (CT) : Current transformer (CT) actually step down the high current to low current for the operation of relays. Current transformer is use for measurement of ... use for relay. This is about potential transformer.

1 like 1 dislike

115 views 1 answer

asked Dec 22, 2017 by anonymous

What is the EMF equation of the transformer?

Last answer: E1 =2(3.142)fN1 (flux)1E2 =2(3.142)fN2(flux)2

3 like 0 dislike

123 views 1 answer

asked Mar 19, 2018 by anonymous

What will happen if the transformers working in parallel are not connected with regard to polarity ?

Last answer: Winding will be damaged

0 like 0 dislike

96 views 2 answers

asked Aug 13, 2019 by Alacrity

the volt per turn of a certain single phase transformers is 1.7. the transformer has a step ratio of 3825/255volt. calculate the respective number of turns in each winding

0 like 0 dislike

49 views 0 answers

asked Apr 29, 2018 by anonymous

Which of the following is the advantage of using CRGO steel in transformers?

Which of the following is the advantage of using CRGO steel in transformers? A) High magnetic flux density B) Low permeability C) Both A and B D) None of these

Last answer: It definitely High Magnetic Flux Density since a crgo steel has always a more around 3% of silicon proportion among the remaining ferrite which make cold rolled grain oriented steel having high flux magnetic ... for more about the crgo core you can learn here https://nicoreindia.com/crgo-core/

0 like 0 dislike

79 views 2 answers

asked May 8, 2018 by anonymous

The friction losses in Real Transformers are :

The friction losses in Real Transformers are : (A) 0% (B) 5% (C) 25% (D) 50%

Last answer: A

0 like 0 dislike

2.5k views 2 answers

asked Aug 8, 2018 by anonymous

Explain the term self induced EMF with a neat diagram.

0 like 0 dislike

56 views 0 answers

asked Aug 8, 2018 by anonymous

List the two types of induced EMF.

Last answer: There are two types of EMF one is statically induced EMF and second is dynamically induced EMF.

0 like 0 dislike

71 views 1 answer

asked Apr 29, 2018 by anonymous

The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors

The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is (1) 1000V (2) 100V (3) 600V (4) 10,000V

Last answer: The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V

0 like 0 dislike

161 views 1 answer

asked Apr 30, 2018 by anonymous

Two 3-phase transformers cannot be operated in parallel, if their :

Two 3-phase transformers cannot be operated in parallel, if their : (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different

Last answer: Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different

0 like 0 dislike

48 views 1 answer

asked Aug 17, 2019 by anonymous

Self induced emf and Mutually induced emf

Last answer: (i) Self-induced e.m.f.: The e.m.f. induced in a coil due to the change of its own flux linked with it, is called self-induced e.m.f. (ii) Mutually induced e.m.f.: The e.m.f. induced in a coil due to the changing current in the neighbouring coil, is called mutually induced e.m.f.

0 like 0 dislike

38 views 1 answer

asked Sep 4, 2018 by anonymous

Compare statically induced emf with dynamically induced emf on any four points.

Last answer: Statically induced emf Dynamically induced emf Emf is induced without any relative motion between conductor and magnetic field. Emf is induced due to relative motion between conductor ... induced in transformer windings e.g emf induced in Generator, Alternator armature windings

0 like 0 dislike

113 views 2 answers

asked Aug 8, 2018 by anonymous

Define: 1) statically induced EMF 2) dynamically induced EMF

Define: 1) statically induced EMF 2) dynamically induced EMF Write the names of equipments in which these two types of EMF get induced

Last answer: Concept of statically induced emf: The emf induced in coil or conductors without any relative motion between it and magnetic field is called statically induced emf. When conductor is stationary and flux ... it. This emf is dynamically induced emf. e.g. Emf induced in generators, alternator.

0 like 0 dislike

370 views 3 answers

asked Apr 28, 2018 by anonymous

The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is

The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is (A) 2/3 (B) 5/6 (C) 7/8 (D) 6/7

Last answer: The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is 6/7

0 like 0 dislike

289 views 1 answer

asked Mar 19, 2018 by anonymous

Two transformers do not have equal percentage impedance. This is likely to result in?

Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?

Last answer: Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.

0 like 0 dislike

69 views 1 answer

asked May 8, 2018 by anonymous

Which of the following connection of transformers will give highest value of secondary voltage ?

Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

Last answer: Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

0 like 0 dislike

105 views 1 answer

asked Mar 19, 2018 by anonymous

If the percentage impedances of the two transformers working in parallel are different, then?

Last answer: If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.

0 like 0 dislike

56 views 1 answer

asked May 8, 2018 by anonymous

Two transformers A and B having equal outputs and voltage ratios but unequal percentage

Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by

Last answer: Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by 33%

0 like 0 dislike

195 views 1 answer

asked May 8, 2018 by anonymous

Core type transformers are popular in___________.

Core type transformers are popular in___________. (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above

Last answer: Core type transformers are popular in High voltage applications

0 like 0 dislike

54 views 1 answer

asked May 8, 2018 by anonymous

In a transmission line if booster transformers are to be used, preferred location will be

In a transmission line if booster transformers are to be used, preferred location will be (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line

Last answer: In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point

0 like 0 dislike

208 views 1 answer

asked Mar 19, 2018 by anonymous

Losses which occur in rotating electric machines and do not occur in transformers are?

Last answer: Friction losses windage losses

0 like 0 dislike

107 views 2 answers

asked Apr 27, 2020 by anonymous

Explain dynamic and static induced emf with neat diagram.

Last answer: Dynamically Induced EMF:- In this case, either coil moves or magnet moves, so that there is relative motion between coil & magnetic field. Thus magnetic field is cut by coil & emf is induced in it. The emf ... The expression for induced EMF is e= -L(di/dt) or = -N(dϕ/dt).

0 like 0 dislike

93 views 1 answer

asked Dec 13, 2019 by UMESH y

Emf definition

0 like 0 dislike

117 views 0 answers

asked Mar 19, 2018 by anonymous

For the parallel operation of single phase transformers it is necessary that they should have?

Last answer: Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers: 1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.

0 like 0 dislike

111 views 2 answers

asked Apr 29, 2018 by anonymous

An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Last answer: An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

0 like 0 dislike

81 views 1 answer

asked Mar 19, 2018 by anonymous

Natural oil cooling is used for transformers up to a rating of?

Last answer: Natural oil cooling is used for transformers up to a rating of 3000 kVA.

0 like 0 dislike

130 views 1 answer

asked Mar 19, 2018 by anonymous

Short circuit test on transformers is conducted to determine?

Last answer: Short circuit test on transformers is conducted to determine copper losses.

0 like 0 dislike

106 views 1 answer

asked Mar 19, 2018 by anonymous

Natural air cooling is generally restricted for transformers up to?

Last answer: Natural air cooling is generally restricted for transformers up to 1.5 MVA .

0 like 0 dislike

140 views 1 answer

asked Aug 30, 2018 by anonymous

Classify the transformers based on the construction, frequency and power.

Last answer: Classification of Transformer Based On: i) Construction: Shell type, Core type, Berry type ii) Change in voltage level: Step-Up, Step-Down, iii) Number of phases: Single phase, Three phase iv) ... Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled.

0 like 0 dislike

105 views 1 answer

asked Mar 19, 2018 by anonymous

The efficiency of two identical transformers under load conditions can be determined by?

Last answer: The efficiency of two identical transformers under load conditions can be determined by back-to-back test.

0 like 0 dislike

107 views 1 answer

asked Mar 19, 2018 by anonymous

The efficiencies of transformers compared with that of electric motors of the same power are?

Last answer: Transformers have high efficiency than the same ratted motors

0 like 0 dislike

93 views 2 answers

asked Mar 21, 2018 by anonymous

Instrument transformers are?

Last answer: Instrument transformers are potential transformers, current transformers.

0 like 0 dislike

56 views 1 answer

asked Mar 19, 2018 by anonymous

Distribution transformers are generally designed for maximum efficiency around?

Last answer: Distribution transformers are generally designed for maximum efficiency around 50% load.

0 like 0 dislike

90 views 1 answer

asked Mar 19, 2018 by anonymous

Power transformers are generally designed to have maximum efficiency around?

Last answer: Power transformers are generally designed to have maximum efficiency around near full-load.

0 like 0 dislike

74 views 1 answer

asked Dec 17, 2017 by anonymous

Why do transformers make noise?

Last answer: Transformers make noise based on it out put if an transformer outputs is 400v maximum than a 398v be apply to that transformer it also make a noise because of that

1 like 0 dislike

72 views 1 answer

asked Sep 18, 2018 by anonymous

What is back emf in DC motor? Explain its significance.

Last answer: Back emf: When the armature of DC motor rotates under the fixed magnetic field and cuts it, by Faraday's law an emf is induced in them. The induced emf acts in opposite direction to the ... the flow of armature current i.e. it automatically changes the armature current to meet load requirements.

0 like 0 dislike

45 views 1 answer

asked Jul 24, 2019 by Deepak kumar bharti

What is largest rating transformer

0 like 0 dislike

2.5k views 0 answers

asked Apr 10, 2018 by anonymous

If the back emf of a dc motor is doubled and its speed is also doubled, the torque developed in the machine...

If the back emf of a dc motor is doubled and its speed is also doubled, the torque developed in the machine will (1) get doubled (2) become 4 times (3) get halved (4) remain unaltered

0 like 0 dislike

155 views 0 answers

What is the back EMF in Transformers?

Please log in or register to add a comment.

Please log in or register to answer this question.

0 Answers

Related questions