What happens if there is no back EMF?

What happens if there is no back EMF?

If there is no back end then large current flows in starting of motors because initial speed is zero and back emf is zero thus winding gets damaged for this purpose only we use starters for all motors. motor will not start. when the motor runs,there has to be back emf.

What is back EMF and its importance?

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.

What is the importance of a counter EMF?

The emf that opposes the flow of current. Just as the windings of a generator produce voltage, the rotor in a motor produces voltage that is counter or opposed to the supply voltage. This counter emf creates additional resistance that must be overcome by the supply voltage.

How do you solve back EMF?

Solution

1. The back emf is ϵi=ϵS−I(Rf+REa)=120V−(10A)(2.0Ω)=100V.
2. 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 back EMF?

The back emf is calculated based on the difference between the supplied voltage and the loss from the current through the resistance. 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.

What happens to the counter EMF in a series motor?

As the motor slows down and the counter emf decreases, more current flows through the armature, but the magnetism in the field is unchanged. When the series motor slows down, the counter EMF decreases and more current flows through the field and the armature, thereby strengthening their magnetic fields.

Is there back EMF in an induction motor?

2 Answers. There is back EMF in an induction motor, but that concept is not used in the equivalent circuit of an induction motor as it is in a DC motor.