What is meant by back emf in dc motor?
What is Back EMF?
When the armature of a DC motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence emf is induced in them as in a generator.
The induced emf acts in opposite direction to the applied voltage V (Lenz’s law) and is known as Back EMF or Counter EMF (Eb).
The equation to find out back emf in a DC motor is given below,
The back emf Eb(= PΦZN/60 A) is always less than the applied voltage V, although this difference is small when the motor is running under normal conditions.
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25 авг 2020