This assignment will familiarize you with the physics of the electric motor you
ID: 1644523 • Letter: T
Question
This assignment will familiarize you with the physics of the electric motor you will build in lab. It is due at the beginning of the electric motor lab period. A schematic diagram of the motor is shown in Fig. 1 of the lab write-up and is reproduced here: Assume the rotor is in the position shown and the current in the rotor loop is as shown. If we replace the loop with a bar magnet having the same magnetic field, in what direction would the north magnetic pole of the bar magnet point? Using the diagram as shown, determine the direction of the force on the wires, Show the direction of the torque on the rotor, and hence the direction of rotation.Explanation / Answer
1) Upward
Because, The loop produces magnetic field in the upward direction.
2) The direction of magnetic force on the right segment is downward.
we use, F = I*(L cross B)
= B*I*L*sin(90)
= B*I*L
The direction of magnetic force on the right segment is upward.
we use, F = I*(L cross B)
= B*I*L*sin(90)
= B*I*L
There is no magnetic force on the remaing two segments. Since the angle between I and B is 0 degrees or 180 degrees.
3) The direction of torque is clockwise.
T = F*(L/2) + F*(L/2)
= F*L