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Normally emf can be calculated by the following formula

e=N*(dф/dt) where dф/dt = rate of change of flux linkages

In actual practice it is given as e=-[N*(dф/dt) ] because as per lenzs law the voltage induced in a direction to oppose the very cause for it i.e., change in flux linkages.

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How do you prove the existence of back EMF?

How do you proof of the existence of back emf ?


Why the generator does not back emf?

A generator does produce back electromotive force (back EMF) as a result of electromagnetic induction. This back EMF opposes the applied voltage and limits the current flowing into the generator. However, if you are referring to a specific scenario or condition under which a generator might not exhibit back EMF, such as when it is operating at no load or when it is stalled, then it may not generate significant back EMF. In those cases, the lack of mechanical motion or load leads to minimal electrical generation.


Does motional emf call induced emf?

yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.


What does an increase in field strength in a dc generator causes a?

increased Back emf


How does the back emf in a dc motor make the motor self regulating?

Back electromotive force (back EMF) in a DC motor is generated as the motor's armature rotates within a magnetic field, opposing the applied voltage. This back EMF increases with the motor's speed, effectively reducing the net voltage across the armature and, consequently, the current flowing through it. As the load on the motor increases, the speed decreases, resulting in a lower back EMF, which allows more current to flow and provides additional torque. This self-regulating behavior helps maintain a relatively constant speed under varying load conditions.

Related Questions

How do you prove the existence of back EMF?

How do you proof of the existence of back emf ?


What is the average induced emf in the loop?

The average induced electromotive force (emf) in the loop is the average amount of voltage generated in the loop due to a changing magnetic field.


Why the generator does not back emf?

A generator does produce back electromotive force (back EMF) as a result of electromagnetic induction. This back EMF opposes the applied voltage and limits the current flowing into the generator. However, if you are referring to a specific scenario or condition under which a generator might not exhibit back EMF, such as when it is operating at no load or when it is stalled, then it may not generate significant back EMF. In those cases, the lack of mechanical motion or load leads to minimal electrical generation.


Can back emf in an inductor be in the same sense as emf of source?

yes..only the application is different.


Does motional emf call induced emf?

yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.


What is Counter Force?

It is also called back EMF. Back EMF is the electric potential difference that opposes the current that induces it. See related link below.


What is Back emf of DC motor?

In dc motor, the armature conductors are revolving in the magnetic field and emf is induced in the armature conductors. The direction of the induced emf is in opposite direction to the applied voltage as per Flemings left hand rule. So, the induced emf in motor is called as back emf or counter emf. Vydehi


What is counter electro-magnteic force?

It is also called back EMF. Back EMF is the electric potential difference that opposes the current that induces it. See related link below.


What is emf induced in a motor's coil that tends to reduce the current in the coil of the motor?

BACK emf induced in a motor's coil that tends to reduce the current in the coil of the motor. The answer should be 'back'.


What is significance of back emf?

According to motor eq. Eb=v-Ia.Ra.And the speed of motor is directly proportional to back EMF.At starting of motor speed is 0,so that Eb is also 0.As the speed increases ,Eb also increases,so that armature current decreases.As the Eb decreases ,so that Ia increases.In this way the back EMF makes the motor self regulating to take armature current as per requriment of motor.Because of this reason EMF also called governor principle of DC motor.This is most important significance of Back EMF. The back EMF is Explaned with lenses Law


What is the Opposition to current flow in a inductive ac circuit?

Back EMF.


What is the significance of emf?

According to motor eq. Eb=v-Ia.Ra.And the speed of motor is directly proportional to back EMF.At starting of motor speed is 0,so that Eb is also 0.As the speed increases ,Eb also increases,so that armature current decreases.As the Eb decreases ,so that Ia increases.In this way the back EMF makes the motor self regulating to take armature current as per requriment of motor.Because of this reason EMF also called governor principle of DC motor.This is most important significance of Back EMF. The back EMF is Explaned with lenses Law