Die-Cast Copper Motor Rotors: Motor Test Results, Copper Compared to Aluminum
Motor manufacturers have long realized that because the electrical conductivity of copper is nearly 60% higher than that of aluminum, substituting copper for aluminum in the squirrel cage of the induction motor would markedly increase the electrical energy efficiency of the machine. Most motors larger than about 200 kW and a few special purpose smaller motors are built with copper squirrel cage structures manufactured by a time consuming and costly fabrication process. The intricate squirrel cage of smaller motors is produced by pressure die casting aluminum. Alternative cost-effective manufacturing methods have not been devised. A major barrier to adoption of copper for the rotor has been the high cost resulting from the short die life of the ordinary die steels experienced in die casting copper with its high melting temperature (1083°C compared to 660°C for aluminum).
Development of 0.5 HP induction motor with reduced slots in rotor and stator core and its performance evaluation
In this paper, we have developed a new prototype of 0.5 hp induction motor with reduced slots in rotor bar and stator core in comparison to the conventional induction motor. The conventional induction motor usually uses 30 slots of aluminum rotor bar and 36 slots in the stator core. In our developed prototype, we used 10 slots of copper rotor bar and 24 slots in the stator core. In order to evaluate the performance of this new prototype, we measured various losses such as core loss, copper loss, friction and windage losses, rotor loss and stray loss and compared them with the 0.5 hp conventional induction motor. The comparison results revealed that the developed prototype provide with a significant reduction, the motor losses. As a result, the efficiency of the new prototype is greatly improved. 
 
   
 
 Key words: Induction motor, 10 slots copper rotor bar, 24 slots stator core, non-grain materials.
Global Islamic Politics
1. Introduction to Islam and Islamic Revivals. 2. Islam: A Vehicle for Political Action. 3. The Muslim Fundamentalists. 4. The Muslim Traditionalists. 5. The Muslim Modernists. 6. The Muslim Pragmatists. 7. Failure of Secular Ideologies and Developmental Crises. 8. Islamic Revivalism in the Arab-Israeli Context. 9. OPEC, OIC, and Islamic Politics. 10. The Islamic Revolution in Iran. 11. Islamic Revival in Central Asia. 12. Conclusion. Glossary of Islamic Terms.