Here v – the velocity of the bar relative to the
magnetic field;
B – magnetic flux density vector;
l – length of conductor in the magnetic field.
The bars at the top of the rotor are moving to the right
relative to the magnetic field: a voltage, with direction
out of page, will be induced. Similarly, the induced
voltage is into the page in the bottom bars. These
voltages produce a current flow out of the top bars and
into the bottom bars generating a winding magnetic
field Bw to the right. Two magnetic fields will create a
torque