Induction motor is the most widely used electric machine. There are two types of induction motor rotors which can be placed inside of the stator. One is called a squirrel cage rotor, while the other is a wound rotor.
The squirrel cage rotor consists of conducting bars which are laid into slots carved in the face of the rotor and shorted at either end by large shorting rings. Because of simple and durable structure, low cost for operation and high efficiency, the squirrel cage induction motor has extensive application in the industry fields.
In recent years, the use of that motor for various fans has been also on an increasing trend.
This paper presents a newly developed double squirrel cage induction motor for the fan and the facilities like that. All of the existing induction motors are composed of two parts, rotor and stator, and the position of rotor is exclusively the inside of stator. However, the rotor of the developed induction motor is located outside the stator.
The outside rotor type brushless dc motor has been often used for VTR's head drum and PC's cooling fan these days, but this kind of induction motor has not been developed yet.
It is believed that the outside rotor type induction motor is suitable for the fan due to its large inertia which can reduce the change of air flow rate resulting from input power or load fluctuation.
In this paper, two tests for obtaining the electrical parameters of the outside rotor type induction motor, which are locked rotor test and no load test, are described and those parameters are measured. Then, to find torque-speed curve, load test is carried out using a dynamometer and the program for motor performance.
And, the developed induction motor is compared with the existing one in terms of torque, efficiency, power factor and output characteristics.
The results of this paper are supposed to be used for the exploitation of the outside rotor type induction motor.