What is the emf equation for generator?

What is the emf equation for generator?
by

1 Answer

Answer :

emf = P * φ * Z * N / A * 60

Where,

φ = Flux per pole in Weber.

Z = Total number of armature conductors.

P = Number of poles.

A = Number of parallel paths in armature.

N = Speed in rpm.

emf = emf generated in one parallel path and it is the emf generated of that generator.

For a wave wound generator there are only two (2) parallel paths in the armature. In

such cases A=2 and in lap wave wound armature parallel paths is equal to the

number of poles in the armature winding. 
by

Related questions

What is the emf equation for DC generator?

Description : What is the emf equation for DC generator?

Last Answer : A = number of parallel paths. That is for lap winding it is equal to Z and for wave winding it equal to 2. 

The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

Description : The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

Last Answer : Answer: D

EMF equation of the transformer?

Description : EMF equation of the transformer?

Last Answer : A. E = 4.44ΦmfN Volts. If E1 & E2 are primary and secondary emf’s and N1 & N2 are primary and secondary turns then, Voltage ratio= E1/E2 and Turns ratio of transformer = N1/N2 E1/E2 = N1/N2

Write down the equation for frequency of emf induced in an Altenator.

Description : Write down the equation for frequency of emf induced in an Altenator.

Last Answer : F = (PN)/120 Hz,Where P- Number of poles, N-Speed in rpm

What is the EMF equation of transformer?

Description : What is the EMF equation of transformer?

Last Answer : Erms = 4.44 f Φ maxT volt

What is the emf equation for transformer?

Description : What is the emf equation for transformer?

Last Answer : Always maximum flux reaches from zero to maximum in one quarter of the cycle. That is in of second. That is equal to 1/200 second. Average rate of change of flux = Qm / f. = Qm * 4 * f. = 4 f Qm Weber / ... * form factor. ∴ rms. Value of emf = 1.11 * 4 f Qm N volts. = 4.44 f Qm N volts.

What is the equation used to find out frequency of number of cycles of induced emf?

Description : What is the equation used to find out frequency of number of cycles of induced emf?

Last Answer : f = NP/120

What is the effect on the magnitude of emf generated in an AC generator if the speed of rotation is increased?

Description : What is the effect on the magnitude of emf generated in an AC generator if the speed of rotation is increased?

Last Answer : The magnitude of emf generated increases.

The Faraday’s law states about which type of EMF? a) Transformer EMF b) Back EMF c) Generator EMF d) Secondary EMF

Description : The Faraday’s law states about which type of EMF? a) Transformer EMF b) Back EMF c) Generator EMF d) Secondary EMF

Last Answer : a) Transformer EMF

In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate

Description : In the plane of AC generator coil is parallel to the field, then emf induced in coil is: a. maximum b. minimum c. zero d. intermediate

Last Answer : b. minimum

In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value

Description : In the plane of the A.C generator coil is perpendicular to the field, then induced emf in the coil is: a. Maximum b. minimum c. zero d. intermediate value

Last Answer : b. minimum

What is EMF Equation in Transformer ?

Description : What is EMF Equation in Transformer ?

Last Answer : Answer : When AC voltage is applied to the primary of the transformer, current is generated. Which produces variable flux in the primary and goes to the secondary through the core. This variable flux expresses the emf in the primary and secondary of the transformer, which is called the emf equation.

6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Description : 6 The value of flux involved in the emf equation of a transformer is A. rms value B. rms value C. Maximum value D. Instantaneous value

Last Answer : C) maximum value

Write emf equation of a transformer.

Description : Write emf equation of a transformer.

Last Answer : E.M.F equation of transformer is given by where Фm= Maximum value of ac flux linking with primary and secondary winding. f = frequency of applied ac signal N= number of turns on primary or ... in primary = E1=4.44 Фm f N1volts  Voltage induced in primary = E2=4.44 Фm f N2volts

Write the Emf equation of transformer. State the meaning of each term in it.

Description : Write the Emf equation of transformer. State the meaning of each term in it. 

Last Answer : EMF equation of Transformer:- E1 = 4.44 f ØmN1 OR E1 = 4.44 f BmAN1 E2 = 4.44 f ØmN2 OR E2 = 4.44 f Bm AN2 Let, E1 = Primary emf E2 = Secondary emf N1= Number of turns in the primary N2 ... flux in core (wb) Bm= Flux density (wb/m2 /Tesla) A= Area of cross section of core m2 F = Frequency 

Define self induced Emf. Write equation of self induced Emf.

Description : Define self induced Emf. Write equation of self induced Emf. 

Last Answer : Definition: Self-induced emf is the e.m.f induced in the coil due to the change of flux produced by linking it with its own turns. Or Self induced emf is that which is induced in a coil, due to the change in its own current or flux. Self induced emf equation. E = - N (dΦ/dt) volts

(a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. (f) State the EMF equation of a 1 transformer and state the meaning of each term used. (g) Give two applications of single phase motors.

Description : (a) Define permeability. (b) Define MMF. (c) Define form factor of an alternating quantity. (d) Define frequency and time period of an alternating quality. (e) Define transformation ratio of transformer. ... and state the meaning of each term used. (g) Give two applications of single phase motors. 

Last Answer : Permeability : It is the ability of a magnetic/Non magnetic material to allow setting up of flux in it.  MMF : The magneto motive force (MMF) is the force required to setup flux in a magnetic / ... applications of single phase motors : Water pumps, ceiling fan, lathe machine

What is the EMF equation of the transformer?

Description : What is the EMF equation of the transformer?

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

The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Description : The emf of a primary cell depends upon the: a) Physical dimension of the cell b) Nature of the electrolyte c) Nature of the electrode d) Both (b) and (c)

Last Answer : Ans: D

Which of the following statements describes what will occur if the motor shown in the illustration is required to carry 150% of full load? EL-0056 A. The primary counter emf will be increased. B. The stator current will increase. C. The slip will decrease. D. The slip value, stator current curve, and torque curve will all coincide.

Description : Which of the following statements describes what will occur if the motor shown in the illustration is required to carry 150% of full load? EL-0056 A. The primary counter emf will be increased. B. ... slip will decrease. D. The slip value, stator current curve, and torque curve will all coincide.

Last Answer : Answer: B

An increase in the amount of current flow through the armature of a shunt motor is the final result of a/an _____________. A. increase in the load on the motor B. decrease in the load on the motor C. increase in counter EMF D. decrease in armature torque

Description : An increase in the amount of current flow through the armature of a shunt motor is the final result of a/an _____________. A. increase in the load on the motor B. decrease in the load on the motor C. increase in counter EMF D. decrease in armature torque

Last Answer : Answer: A

In the illustration, the diode between terminals 16 and 17 is to _________. EL-0046 A. insure that the voltage across the governor coil (EG-3P) never exceeds .6 VDC B. compensate for the temperature difference of the governor oil heating up C. protect the electronic governor from counter EMF D. act as a filter to prevent hunting

Description : In the illustration, the diode between terminals 16 and 17 is to _________. EL-0046 A. insure that the voltage across the governor coil (EG-3P) never exceeds .6 VDC B. compensate for the ... heating up C. protect the electronic governor from counter EMF D. act as a filter to prevent hunting

Last Answer : Answer: C

The counter EMF of a DC motor is maximum when the _________. A. motor is at rated speed B. armature is not turning C. motor is almost up to rated speed D. armature has just begun to turn

Description : The counter EMF of a DC motor is maximum when the _________. A. motor is at rated speed B. armature is not turning C. motor is almost up to rated speed D. armature has just begun to turn

Last Answer : Answer: A

The counter EMF produced in the windings of a DC motor is 'zero' when the ____________. A. armature has just begun to turn B. armature is not turning C. motor is almost up to rated speed D. motor is at rated speed

Description : The counter EMF produced in the windings of a DC motor is 'zero' when the ____________. A. armature has just begun to turn B. armature is not turning C. motor is almost up to rated speed D. motor is at rated speed

Last Answer : Answer: B

Which of the following types of DC motors has its field connected in parallel with its armature? A. Counter EMF B. Shunt C. Salient pole D. Series

Description : Which of the following types of DC motors has its field connected in parallel with its armature? A. Counter EMF B. Shunt C. Salient pole D. Series

Last Answer : Answer: B

The ratio of the effective value of the counter EMF in volts, to the effective value of the current in amperes is called _____________. A. impedance factor B. capacitive reactance C. inductive reactance D. root mean square

Description : The ratio of the effective value of the counter EMF in volts, to the effective value of the current in amperes is called _____________. A. impedance factor B. capacitive reactance C. inductive reactance D. root mean square

Last Answer : Answer: C

The unit of apparent power in a purely inductive circuit is called the _____________. A. kva B. var C. emf D. watt

Description : The unit of apparent power in a purely inductive circuit is called the _____________. A. kva B. var C. emf D. watt

Last Answer : Answer: B

What are the advantages and disadvantages of estimating the voltage regulation of an Alternator by EMF method?

Description : What are the advantages and disadvantages of estimating the voltage regulation of an Alternator by EMF method?

Last Answer : Advantages: · Simple no load tests (for obtaining OCC and SCC) are to be conducted · Calculation procedure is much simpler Disadvantages: · The value of voltage regulation obtained by this method is always higher than the actual value

How the frequency of rotor emf is related to the slip in an I M?

Description : How the frequency of rotor emf is related to the slip in an I M?

Last Answer : Frequency of rotor emf/current fr=Sf

How the magnitude of rotor emf is related to the slip in an I M?

Description : How the magnitude of rotor emf is related to the slip in an I M?

Last Answer : Rotor circuit emf per phase E2’=SE2

How we can find the direction of induced emf?

Description : How we can find the direction of induced emf? 

Last Answer : The direction of induced emf can be find out by the Fleming's right hand rule', and lenz's law' Fleming's right hand rule : Fleming's right hand rule states that, if ... that the action of magnetic field set up by induced current tends to opposes the root cause which produces it. 

What is electro-motive force (emf) or voltage?

Description : What is electro-motive force (emf) or voltage?

Last Answer : It is the pressure that moves the electrons to flow in any conductor. It is also known as electromotive force voltage. Its symbol is ‘E’ or ‘V’ and measuring unit is volt measured by voltmeter. 

Why back emf used for a dc motor? highlight its significance.

Description : Why back emf used for a dc motor? highlight its significance.

Last Answer : The induced emf developed when the rotating conductors of the armature between the poles of magnet, in a DC motor, cut the magnetic flux, opposes the current flowing through the conductor, when the ... speed of rotation of the armature conductors. In starting, the value of back emf is zero.

A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Description : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf? (A) 100 Volts. (B) 0.1 Volts. (C) 1 Volts. (D) 10 Volts.

Last Answer : Ans: D Given N = 1500 rpm, Φ = 0.4 mWb, Z = 1000, P = 4, & A= 4 Therefore, Eb = NΦPZ / 60 A = 1500 x 0.4 x 4 x 1000 x 10^-3 / 60 x 4 = 60/6 = 10 volts

Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Description : Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the frequency of the rotor induced emf? (A) 10 Hz. (B) 50 Hz. (C) 1 Hz. (D) 2500 Hz.

Last Answer : Ans: C Given : s = 0.02 ; f = 50 Hz Therefore, frequency of rotor induced emf = s f = 0.02 x 50 = 1.0 Hz

The emf induced in the primary of a transformer (A) is in phase with the flux. (B) lags behind the flux by 90 degree. (C) leads the flux by 90 degree. (D) is in phase opposition to that of flux.

Description : The emf induced in the primary of a transformer (A) is in phase with the flux. (B) lags behind the flux by 90 degree. (C) leads the flux by 90 degree. (D) is in phase opposition to that of flux.

Last Answer : (C) leads the flux by 90 degree.

The angle δ in the swing equation of a synchronous generator is the

Description : The angle δ in the swing equation of a synchronous generator is the  (A) angle between stator voltage and current (B) angular displacement of the rotor with respect to the stator (C) angular ... (D) angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis

Last Answer : The angle δ in the swing equation of a synchronous generator is the angular displacement of an axis fixed to the rotor with respect to a synchronously rotating axis

Induction generator is self excited machine. a) True b) False

Description : Induction generator is self excited machine. a) True b) False

Last Answer : Ans: B

Voltage build up in an isolated induction generator depends on A. Capacitor bank value B. Residual magnetism of the rotor iron C. Residual magnetism of the stator iron a) A, B b) A, B, C c) B d) A, C

Description : Voltage build up in an isolated induction generator depends on A. Capacitor bank value B. Residual magnetism of the rotor iron C. Residual magnetism of the stator iron a) A, B b) A, B, C c) B d) A, C

Last Answer : Ans: A

If the residual flux is absent in the rotor iron of the isolated induction generator, a) it will not run. b) it will run as induction motor c) it will burn the winding d) it will not affect the characteristic of the generator

Description : If the residual flux is absent in the rotor iron of the isolated induction generator, a) it will not run. b) it will run as induction motor c) it will burn the winding d) it will not affect the characteristic of the generator

Last Answer : Ans: A

Induction generator a) can not work in isolation b) can work in isolation c) should work in parallel with synchronous generators d) any of the mentioned

Description : Induction generator a) can not work in isolation b) can work in isolation c) should work in parallel with synchronous generators d) any of the mentioned

Last Answer : Ans: C

According to Coast Guard Regulation (46 CFR) for emergency power and lighting systems, which of the listed items is the only permissible starting aid for the emergency diesel generator engine? A. Ether B. Lube oil heater C. Jacket water heater D. Fuel oil heater

Description : According to Coast Guard Regulation (46 CFR) for emergency power and lighting systems, which of the listed items is the only permissible starting aid for the emergency diesel generator engine? A. Ether B. Lube oil heater C. Jacket water heater D. Fuel oil heater

Last Answer : Answer: C

Coast Guard Regulations (46 CFR) require that each alternating current generator arranged for parallel operation shall be provided with _____________. A. more than one means of excitation B. individual circuit fuses C. a high back-pressure trip D. a reverse-power trip

Description : Coast Guard Regulations (46 CFR) require that each alternating current generator arranged for parallel operation shall be provided with _____________. A. more than one means of excitation B. individual circuit fuses C. a high back-pressure trip D. a reverse-power trip

Last Answer : Answer: D

An emergency generator, driven by an internal combustion engine, shall be tested under load for a minimum of 2 hours at least once every _____________. A. week B. 2 weeks C. month D. 3 months

Description : An emergency generator, driven by an internal combustion engine, shall be tested under load for a minimum of 2 hours at least once every _____________. A. week B. 2 weeks C. month D. 3 months

Last Answer : Answer: C

Coast Guard Regulations (46 CFR) require that the emergency diesel generator engine shut down when _____________. A. lubricating oil pressure is lost B. the engine overspeeds dangerously C. fixed CO2 is released into the emergency diesel generator space D. all of the above

Description : Coast Guard Regulations (46 CFR) require that the emergency diesel generator engine shut down when _____________. A. lubricating oil pressure is lost B. the engine overspeeds dangerously C. fixed CO2 is released into the emergency diesel generator space D. all of the above

Last Answer : Answer: D

The shipboard general alarm system must receive its main source of power from _____________. A. a storage battery B. the emergency generator C. an auxiliary generator D. the ship's service generator

Description : The shipboard general alarm system must receive its main source of power from _____________. A. a storage battery B. the emergency generator C. an auxiliary generator D. the ship's service generator

Last Answer : Answer: A

The source of emergency lighting and power at loss of normal ship's power on a cargo vessel should be obtained from the ______________. A. emergency generator supply to the emergency switchboard B. emergency generator supply to the main switchboard C. battery supply to the main switchboard D. turbogenerator supply to the emergency switchboard

Description : The source of emergency lighting and power at loss of normal ship's power on a cargo vessel should be obtained from the ______________. A. emergency generator supply to the emergency ... switchboard C. battery supply to the main switchboard D. turbogenerator supply to the emergency switchboard

Last Answer : Answer: A

In the schematic diagram of the DC compound generator shown in the illustration, the positive ammeter reading is 500 amps and the negative ammeter reading is 475 amps. What is the current flow through the neutral bus? EL-0037 A. 0 amp B. 12.5 amp C. 25 amp D. 975 amp

Description : In the schematic diagram of the DC compound generator shown in the illustration, the positive ammeter reading is 500 amps and the negative ammeter reading is 475 amps. What is the current flow through the neutral bus? EL-0037 A. 0 amp B. 12.5 amp C. 25 amp D. 975 amp

Last Answer : Answer: C

Moving the rheostat handle shown in the illustration, that is used to control a DC generator, towards the 'raise' direction will increase the _____________. EL-0030 A. field resistance B. armature resistance C. armature speed D. line voltage

Description : Moving the rheostat handle shown in the illustration, that is used to control a DC generator, towards the 'raise' direction will increase the _____________. EL-0030 A. field resistance B. armature resistance C. armature speed D. line voltage

Last Answer : Answer: D