# How to design a single phase induction motor

1. May 21, 2015

### AlexiaIoannou

Hi everyone....
I have to design a single phase induction motor.
I have some questions and it would be great if you could help me. The parameters I have for the design of the motor are: rated power, rated voltage, frequency, rated speed, power factor, efficiency, full load current and full load torque.
I need some information of how to calculate other parameters, such as flux density, core length, air gap, size of both stator and rotor and their slots etc. I have found some equations for calculating all these for a 3 phase induction motor and I wonder if I can use them for the singe phase induction motor too.
I really appreciate your help , thank you very much!

2. May 21, 2015

### Hesch

I don't know as I have not seen your equations.

As for a single phase motor you need only one (primary) winding. The motor can run, but it cannot start because it does not know in which direction to start. ( You can only induce a magnetic field in one dimension, which leaves no "space" to create angles ).

Therefore you must have an extra "starting coil" that has an electrical angle of say 90° as to the primary winding. This angle is provided by connecting a capacitor in series with the starting coil, thereby making a current phase shift in the starting coil and a "second dimension". So the coils in the single phase motor are not symmetrical as in the 3 phase motor, and thus (some of) the equations for the 3 phase motor cannot be used by the single phase motor.

This is very hard to explain in short.

3. May 21, 2015

### AlexiaIoannou

How could i find these equations refering to the single-phase motor? Is there any paper or something?

4. May 24, 2015