What does counter electromotive force do?

Counter-electromotive force (counter EMF, CEMF), also known as back electromotive force (back EMF), is the electromotive force (voltage) that opposes the change in current which induced it.

What is counter electromotive force in a motor?

counter electromotive force. 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. CAA.

What is counter emf measured in?

volts
It’s measured in volts, and is sometimes equated with voltage, or potential difference. The tutorial below describes both EMF and a related phenomenon, back EMF (or counter EMF).

How does counter emf help DC motor?

The decreased back emf allows a larger current to flow through the armature and larger current means increased driving torque. Thus, the driving torque increases as the motor slows down. The motor will stop slowing down when the armature current is just sufficient to produce the increased torque required by the load.

Why is back EMF important?

Significance of Back EMF in DC Motor As the speed of the armature increases, the back emf also increases and causes the armature current is decrease. The motor will stop accelerating when the armature current is sufficient to develop the torque required by the load.

What is back EMF explain?

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 happens if motor back EMF is 0?

As the back emf vanishes zero, the whole supply voltage appears across armature and heavy current flows. If supplying unit didn’t trip down by this time, excess current in armature may heat up the armature and it may cause burning of armature winding.

What is counter emf in DC motor?

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).

What is counter EMF in transformer?

The induced e.m.f. acts in opposite direction to the applied voltage V (Lenz’s law) and in known as back or counter e.m.f. Eb.

Why is back EMF necessary?

The significance of Back EMF Back emf is very significant in the working of a dc motor. The presence of back emf makes the d.c. motor a self-regulating machine i.e., it makes the motor to draw as much armature current as is just sufficient to develop the torque required by the load.