Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way are these simple electric motors different from commercial motors?

(N/A) Working of an electric motor: An electric motor consists of a rectangular coil $ABCD$ of insulated copper wire placed between the two poles of a magnetic field. The ends of the coil are connected to the two halves $P$ and $Q$ of a split ring. The inner sides of these halves are insulated and attached to an axle. The external conducting edges of $P$ and $Q$ touch two conducting stationary brushes $X$ and $Y$. Current in the coil $ABCD$ enters from the source battery through conducting brush $X$ and flows back to the battery through brush $Y$. When current flows through the coil,a magnetic force acts on the arms $AB$ and $CD$. According to Fleming's Left-Hand Rule,the force on arm $AB$ pushes it downwards,while the force on arm $CD$ pushes it upwards. Thus,the coil and the axle rotate in an anti-clockwise direction. At half rotation,$Q$ makes contact with the brush $X$ and $P$ with brush $Y$. Therefore,the current in the coil gets reversed and flows along the path $DCBA$. This reversal of current reverses the direction of force acting on the two arms,and the coil continues to rotate in the same direction.
Differences from commercial motors:
$1$. Commercial motors use an electromagnet in place of a permanent magnet.
$2$. They use a large number of turns of conducting wire in the current-carrying coil.
$3$. They use a soft iron core on which the coil is wound to increase the magnetic field strength.