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27/09/2021 7:58 pm
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Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring an electric motor?
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27/09/2021 8:01 pm
An electric motor is a device which converts electrical energy into mechanical energy.
Construction: It consists of a rectangular coil called armature curved magnet pieces, commutator and carbon brushes.
Principle: It works on the principle that when a current-carrying coil is placed normally in a magnetic field, it experiences a torque which tends to rotate it.
An electric motor
Working:
- When a current flows through the coil, arms AB and CD experience a force. According to Fleming’s left hand rule, arm AB of the coil experiences a force in the downward direction. Similarly, arm CD of the coil experiences a force in the upward direction. Two equal and opposite forces constitute a couple and hence the coil will rotate in anticlockwise direction.
- When the coil reaches the vertical position, no current flows in the coil and no force acts on the coil in this position.
- Now coil rotates further and side AB is moved on the right, with its commutator segment touching the right hand brush so it has downward force acting it. Similarly, side CD has an upward force on it. Thus, the couple always acts in the same direction (clockwise) and the coil spins.