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## What is the emf equation of a motor?

As the armature rotates, a voltage is generated in its coils. In the case of a generator, the emf of rotation is called the Generated emf or Armature emf and is denoted as Er = Eg. In the case of a motor, the emf of rotation is known as Back emf or Counter emf and represented as **Er = Eb**.

## How do you calculate back emf of a motor?

The power from each device is calculated from one of the power formulas based on the given information. The back emf is **ϵi=ϵS−I(Rf+REa)=120V−(10A)**(2.0Ω)=100V. Since the potential across the armature is 100 V when the current through it is 10 A, the power output of the motor is Pm=ϵiI=(100V)(10A)=1.0×103W.

## How do you calculate the emf of a dc motor?

**EMF equation of a DC generator**

- Average emf generated per conductor is given by dΦ/dt (Volts) … eq. …
- Flux cut by one conductor in one revolution = dΦ = PΦ …. (Weber),
- Number of revolutions per second (speed in RPS) = N/60.
- Therefore, time for one revolution = dt = 60/N (Seconds)
- From eq.

## What is the formula of flux per pole?

**Flux= 2πr*l*B**. now, for calculating flux per pole, divide it by P=4. So, Flux per pole after substituting all values is equal to 0.0188 Wb.

## What is emf of cell?

The emf of a cell is **the sum of the electric potential differences (PDs) produced by a separation of charges** (electrons or ions) that can occur at each phase boundary (or interface) in the cell. The magnitude of each PD depends on the chemical nature of the two contacting phases.

## What is the emf equation of alternator?

**V = 4.44 K _{f} K_{C} K_{D} f ΦT Volts**.

Where: V = Actual generated Voltage per phase.

## Is back EMF AC or DC?

**Back EMF can have either a sinusoidal (AC) or a trapezoidal (DC) waveform**. The shape of the back EMF is important, as it determines the type of drive current and commutation method that should be used for the motor.

## What is back EMF of a motor?

Back EMF is **the system in the coil of an electric motor that opposes the current flowing through the coil**, when the armature rotates. When the speed varies, the winding characteristics may fluctuate, resulting in variation of back EMF.

## Why back emf is used in DC motor?

**When the armature of the DC motor rotates under the influence of driving torque, the armature of the conductors moves through a magnetic field inducing an emf in them**. The induced emf is in the opposite direction to the applied voltage and is known as the back emf.

## What is emf in a DC motor?

A motor has coils turning inside magnetic fields, and a coil turning inside a magnetic field induces an emf. This emf, known as the back emf, **acts against the applied voltage** that’s causing the motor to spin in the first place, and reduces the current flowing through the coils of the motor.