Question

Why we need to reverse the polarity of the current in dc?

Answer 1

Here is your answer ⤵⤵⤵

Of course, the direction of current is controlled by the polarity of the voltage. So in order to change the direction of rotation, we can simply reverse the voltage, causing the current to flow in the opposite direction, changing the force by 180 degrees and the motor to be driven 'backwards'.

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Answer 2

for the continuous disturbance in the magnetic field lines.
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