Thursday, 31 March 2011

How electric motor works?

Electric motor is a very important machine component. This is used in many machine i.e. Fan, Washing machine, Electric car. Did you ever thought that how it works. In this article I am explaining electric motor mechanism.

Main components of electric motor are Permanent magnets, Armature(Hard wire) commutators and Brushes. Following is the image of electric motor.

In the above picture you can see two magnets facing their opposite poles towards each other, a armature (Loop of hard coil), commutators and brushes. Electric current is passing through armature and generating a force that rotating the armature. You can see the force indicated by orange arrow. You can figure out force direction with the help of Fleming's Left-Hand Rule as in below picture. 

According to this rule if you hold out your thumb, first finger and second finger of Left hand so that all three are right angles and point your first finger in the direction of field and second finger in the direction of current then thumb will indicates the direction of force. 

So by force armature starts rotating. You can see in the picture that there are two commutators connected with armature ends and touching brushes. When armature rotates so commutator rotates. When armature completed half rotation then automatically commutators exchange the brush because brushes are fixed. So current flow change repeatedly. This helps to complete the full rotation otherwise armature go static after half rotation. In this way armature keep rotating till current is flowing.

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