**Noise of Induction Machines**

Marcel Janda, Ondrej Vitek and Vitezslav Hajek

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/38152

**1. Introduction** 

206 Induction Motors – Modelling and Control

German), VEB Verlag Technik Berlin.

Vogt. V. (1988). Electrical Machines. Design of Rotary Electric Machines, Fourth edition (in

Diagnostics of electric machines is very interesting and extensive. There are many methods used to detect properties of electrical machines. Between diagnostic methods include too the measurement and analyze of noise, which generates electrical machines.

Itself the noise of electric machines is byproduct of the machine operation. The generation of noise is involved in many physical principles.

Noise of electrical machinery is generated by the vibration of machine parts. Gradual spread of vibration from the engine to the surroundings causes pulses of air with certain frequencies. This creates a sound wave generator, which can be within a certain frequency range, audible to humans.

The main sources of noise in electrical machines are time change of the electromagnetic fields, noise of bearings and other mechanical sources. Finally, the unwanted noise is creating too due to coolant flow or parts that come into contact with coolant in electric machines. Level of noise sources in electrical machines depends on the structural arrangement and the accuracy of engine design.

A major problem in measurement noise is interference environment. For a perfect suppression ambient noise is necessary to have a specialized laboratory. It should be also measured machine have isolated from vibration, which it may be transferred from storage.
