Sunday, 22 February 2015

Make the rotation reversed of your fan

Make the rotation reversed of your fan
Sometimes it happens that we need to change the blades of fans. If the new one is not similar with the original one, it can not draw air. It draws air if it is moved in opposite direction. here we need to reverse the rotation o the fan.
We all know that our fan is a single phase AC induction motor. As there is no rotating magnetic field in single phase, single phase motors are not self starting. To solve this problem we temporarily we convert it into a two phase induction motor during starting. For this purpose, the stator of a single phase induction motor is provided with an extra starting winding, called auxiliary winding. The starting winding and the running winding are spaced 90 degree electrically apart from each other. There is a phase difference between starting and running winding current, that is ideally 90 degree. Here capacitor mainly creates that phase difference.
So for reversing the single phase induction motor we need to reverse the connection of capacitor. 

thank you very much