**Acknowledgement**

The presented results are carried out through the researches within scientific projects "New structures for hydro generating unit dynamic stability improvement" and "Revitalization and operating of hydro generator" supported by Ministry of Science, Education and Sports in the Republic of Croatia.

### **8. References**

Ameziquita-Brook, L., Liceaga-Castro, J., Liceaga-Castro, E., (2009). Induction Motor Identification for High Performance Control Design, *International Review of Electrical Engineering*, Vol. 4, No. 5; (October 2009), pp. (825-836) ISSN 1827-6660.

**Chapter 4** 

© 2012 Jimoh et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Jimoh et al., licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Modelling and Analysis of Squirrel Cage** 

**Induction Motor with Leading Reactive** 

Induction motors are by far the most used electro-mechanical device in industry today. Induction motors hold many advantages over other types of motors. They are cheap, rugged, easily maintainable and can be used in hazardous locations. Despite its advantages it has one major disadvantage. It draws reactive power from the source to be able to operate and therefore the power factor of the motor is inherently poor especially under starting conditions and under light load (Jimoh and Nicolae, 2007). Poor power factor adversely affects the economics of distribution and transmission systems and therefore may lead to higher electricity charges (Muljadi et al., 1989). At starting, power drawn by the motor is mainly reactive and it can draw up to 8 times its rated current at a power factor of about 0.2 until it reaches rated speed after which the power factor will increase to more than 0.6 if the

To improve the power factor, reactive power compensation is needed where reactive power is injected. Several techniques have been suggested including synchronous compensation which is complex and expensive. Switched capacitor banks which requires expensive switchgear and may cause voltage regeneration, over voltage and high inrush currents (El-

In this chapter another approach for power factor correction is explored where the stator of an induction motor has two sets of three phase windings which is electrically isolated but magnetically coupled. The main winding is connected to the three phase supply and the

The first part of this chapter focuses on the development of a mathematical model for a normal three phase induction motor, the second part of the chapter focuses on the

auxiliary winding connected to fixed capacitors for reactive power injection.

Adisa A. Jimoh, Pierre-Jac Venter and Edward K. Appiah

motor is properly loaded and depending on the size of the motor.

Additional information is available at the end of the chapter

**Power Injection** 

http://dx.doi.org/10.5772/50011

**1. Introduction** 

Sharkawi et al., 1985).

