International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 08 | Aug 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1734 VIBRATION AND NOISE SIGNAL ANALYSIS OF A GEARBOX HAVING DELRIN GEAR WITH BROKEN TEETH DEFECT Sayeed Ahamed K I 1 , Ramesh Kurbet 2 , Ajit Prasad S L 3 1 PG Student, Dept. of Mechanical Engineering, PESCE Mandya, Karnataka, India 2 Assistant professor, Dept. of Mechanical Engineering, PESCE Mandya, Karnataka, India 3 Professor, Dept. of Mechanical Engineering, PESCE Mandya, Karnataka, India ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - The main objective of this study is to perform vibration and noise analysis of gearbox with healthy and faulty Delrin gears (gear with broken teeth), which can be helpful in pre-emptive recognition of system failure. Whenever the natural frequency of the system coincides with the excitation frequency then the amplitude of vibration reaches maximum causing catastrophic failure of the system. Because of the severity of the effect of vibration on engineering systems it is necessary to carry out vibration and noise tests to avoid failure. The vibration and noise signals were collected from healthy and faulty Delrin gears which were operated under different speed and torque conditions. The vibration and noise signals were sensed by accelerometer and microphone from the gearbox casing, and the signals were recorded using data acquisition system. The results show the gearbox vibration characteristics using time domain analysis, frequency domain analysis and order tracking analysis parameters. And noise characteristics using octave band analysis parameter. A Comparison is done between the signals of healthy and faulty Delrin gear and analysis of the signals show distinct differences in the vibration and noise characteristics between healthy and faulty gear systems. Key Words: Gearbox, Delrin gears, Time domain analysis, Frequency domain analysis, Octave band analysis. 1. INTRODUCTION The gearbox is the primary tool of power transmission. Gears are one of the most significant parts in mechanical transmission systems. [1] It is critical element in a variety of industrial applications, transportation, aerospace, energy, agricultural sectors, wind generation and other fields. Smooth operation and high efficiency of gears are necessary for the normal running of machines. Therefore, gear analysis is an important activity in the field of condition monitoring and fault diagnosis. Early detection of local gear faults in industrial environments is very important to optimize the maintenance schedule and reduce the operating cost of gearbox damage. Failures of the gearbox may cause injury to human beings and important economic losses. To avoid the consequences of any harmful accidents, several techniques are developed in condition monitoring to detect faults as early as possible. Vibration signal analysis is the most common gear detection technique for gear damage detection. [2] Delrin acetal homopolymer also called Delrin Polyoxymethylene [POM-H] is one of the most crystalline engineering thermoplastics available. It is a highly adaptable material which offers an excellent balance of properties that bridge the gap between metals and plastics. It is the stiffest and strongest unreinforced engineering polymer available which is natural replacement for metals. The need for reduced energy consumption and cost through metal- replacement with lightweight engineering polymers is a confirmed trend in the automotive industry, and is increasingly gaining ground in general engineering and many other industry sectors. Delrin possesses high tensile strength, creep resistance and toughness. It also exhibits low moisture absorption. It is chemically resistant to hydrocarbons, solvents and neutral chemicals. The Tooth breakage may be the result of high overloads, repeated overloads causing low-cycle fatigue, or multiple repeated loads leading to high cycle fatigue of the material. Where high stress concentration exists together with highest tensile stress from bending or from the surface defects. The crack slowly propagates over 80 to 90% of the life. Then crack propagates fast and suddenly results in fracture of the tooth. Vibration monitoring and analysis is done because, Vibration is a proven parameter which could be used to monitor the conditions of rotating machinery. Various mechanical faults can be detected by vibration measurement and analysis. Most of the failures in rotating machinery are due to, damaged bearings, gears, belts, vanes of impellers and shafts, assembly faults like unbalance, misalignment, mechanical looseness, bent shaft, and oil whirl in hydrodynamic bearings. All these factors affect the vibration emitted from the machines. Therefore vibration is a good indicator of health of a machine. Due to vibration monitoring of a machine we get the following information: When to change a bearing, gear, belt or carrying out major maintenance activities, how to avoid rejects, defective parts produced by the machine, how to achieve zero breakdown, how to improve productivity. Sound is a simple harmonic acoustic vibrations expressed in terms of tones, sound is single frequency (sinusoidal). Sound