You may be surprÂ­ised to discover that a carbon monoxide (CO) detector really isn't a complicated piece of equipment. Housed inside a plastic chamber approximately 3 inches (7.6 centimeters) in diameter are parts that work in unison to alert a househoÂ­ld when lethal gas is detected.
This type of noise is usually caused by malfunctioning valve lifters or an exhaust manifold leak. If the noise lasts for more than a minute and completely disappears or dimishes after the engine is warm, the most likely cause is an exhaust manifold leak.
Out of various causes which induce harmonics in the air gap, the field effects of stator-rotor slot combinations are the common causes for high magnetic noise in induction motors [3], [4], [5]. Finley [4] discussed various techniques to decrease the magnetic noise in electric motors. A good literature review on this topic could be found in [7]. This paper presents a theoretical model for the prediction of magnetic noise in induction motors. Numerical results are