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When a motor is turning it acts as a generator and produces a back EMF that opposes the applied EMF. See my answer to Top angular speed of electric motorTop angular speed of electric motor for more on this. A frictionless motor would draw no current when not under load, though obviously real motors do draw some current because of frictional losses.

If you load the motor you reduce the back EMF, and because the applied EMF is now greater than the back EMF there is an increased current through the motor.

If you stall the motor completely then it does not generate any back EMF at all, so the applied EMF sends the maximum possible current through the motor, limited only by the resistance of the coil windings. Depending on the motor design this may be high enough to damage the motor.

When a motor is turning it acts as a generator and produces a back EMF that opposes the applied EMF. See my answer to Top angular speed of electric motor for more on this. A frictionless motor would draw no current when not under load, though obviously real motors do draw some current because of frictional losses.

If you load the motor you reduce the back EMF, and because the applied EMF is now greater than the back EMF there is an increased current through the motor.

If you stall the motor completely then it does not generate any back EMF at all, so the applied EMF sends the maximum possible current through the motor, limited only by the resistance of the coil windings. Depending on the motor design this may be high enough to damage the motor.

When a motor is turning it acts as a generator and produces a back EMF that opposes the applied EMF. See my answer to Top angular speed of electric motor for more on this. A frictionless motor would draw no current when not under load, though obviously real motors do draw some current because of frictional losses.

If you load the motor you reduce the back EMF, and because the applied EMF is now greater than the back EMF there is an increased current through the motor.

If you stall the motor completely then it does not generate any back EMF at all, so the applied EMF sends the maximum possible current through the motor, limited only by the resistance of the coil windings. Depending on the motor design this may be high enough to damage the motor.

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John Rennie
John Rennie
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When a motor is turning it acts as a generator and produces a back EMF that opposes the applied EMF. See my answer to Top angular speed of electric motor for more on this. A frictionless motor would draw no current when not under load, though obviously real motors do draw some current because of frictional losses.

If you load the motor you reduce the back EMF, and because the applied EMF is now greater than the back EMF there is an increased current through the motor.

If you stall the motor completely then it does not generate any back EMF at all, so the applied EMF sends the maximum possible current through the motor, limited only by the resistance of the coil windings. Depending on the motor design this may be high enough to damage the motor.