Back Emf help (1 Viewer)

[Glyde]

hey guys,
if back emf opposes the induced emf, then how does the electric motor continue to spin ? isnt is equal and opposite thus cancelling it out?

 

[Fizzy_Cyst]

hey guys,
if back emf opposes the induced emf, then how does the electric motor continue to spin ? isnt is equal and opposite thus cancelling it out?

If Back EMF and supply EMF were equal and opposite, this would mean that there would be no net current flowing through the motor and hence no net torque acting on the coil -- you can think of torque as being the equivalent of 'angular acceleration'. If there is torque, the motor will spin faster, whereas if there is no torque, the motor will keep doing what it's doing (kind of like rotational inertia) and spin at a constant speed.

 

[kashkow]

Equal and opposite as in there are no net forces acting on it, thus it will spin at a constant rate.

I know it's sorta tricky to get your head around and I know it was a little weird for me. But basically if there are no net forces on an object the object moves at a constant rate, and this can be 0 but doesn't need to be.

I think Fizzy_Cysts answer is probably more accurate than mine and definitely explains this specific situation better than mine but I'm giving a more generalised approach for other questions, if you need it

Hope it helps

 

[Glyde]

Thanks both of you so basically back emf just stops the motor from accelerating ?