SMART WHEELCHAIR/VEHICLE FOR PHYSICALLY CHALLENGED PEOPLE WITH REVERSE GEAR OPERATION

This paper aims to design the vehicle for the physically challenged person with reverse gear system. This proposed vehicle helps them not to believe any third persons to require a reverse gear. Here we used \"tumbler gear” mechanism for our prototype where the gear is accustomed by changing the direction of gear. It contains two gears which place in parallel by changing their position with motor direction; that are often changed but in real time application we\'d wish to use ideal gear system with gear box. Also the bike contains ultrasonic sensor which supports echo signals to supply alert on taking reverse to avoid collision between other object. this technique also contains \"GPS\" which help their family to locate the position of the physically challenged person just easily. in case of any emergency, an ultrasonic sensor, GPS module and relay circuits are employed to drive the motor in our prototype.

Analysis and Research on Fracture Cause of Fixed Shaft of Torsion Arm of Wind Turbine Gearbox

In a wind power plant of a wind power plant limited liability company, the fixed shaft of the torsion arm of the gear box broke during the operation of a wind power generator set. In order to find out the cause of fracture, the fracture fixed shaft of torsion arm was comprehensively detected and analyzed by means of appearance morphology analysis, chemical composition analysis, mechanical properties testing, microstructure testing and fracture micro-area analysis. The results show that the main reasons for the fracture of the fixed shaft of the torsion arm of the fan gear box are as follows: improper heat treatment process of the fixed shaft of the torsion arm of the gear box causes a large amount of massive ferrite in the material structure, resulting in insufficient strength of the material; the inclusion in the material is serious, resulting in unqualified impact toughness; Shaft surface surfacing Cr - Mn stainless steel material causes the fusion zone C migration form brittle layer, at the same time the vast difference between the state of welding layer and substrate organization fusion zone caused by larger remnants stress, the embrittlement in bond layer to form the intergranular crack crack source, and in the process of the equipment operation under the action of cyclic torsional and impact load, Cracks propagate in a fatiguing manner and lead to eventual fracture.

Case Study: Consecutive Failure of Lube Oil Cooler Fans Coupling

Do we analyze on why can even the most reliable turbomachinery are getting failure and stopped? In some cases, it's all about bad installation or design literally. This paper explores the challenges one site had with repeated failure of lube oil fin fan coolers coupling which caused the unit availability of more than 3 months. It outlines the troubleshooting attempts made to remedy this issue, its root cause, and the resulting solution. This issue occurred at a site with a train configuration of motor driven centrifugal compressors. The plant lube oil system has been configured with 3 trains. Each train has been configured with Main electric motor + Vorecon Gearbox + Low Pressure centrifugal compressor + High Pressure centrifugal compressor. Lube oil system of the train has been configured as 2 lube oil coolers and 2 working oil coolers. Lube oil coolers are having fins with air cooler type. Air is supplied by fin fans and each train has 2 lube oil cooler fans and 2 working oil cooler fans. In total site has 3 trains x 4 fin fans so it has 12 fin fan cooler fans. All cooler fans are driven by electric motor which is coupled with gearbox and gear box is connected with cooler fan. During normal operation of working oil cooler fan A- stopped rotation suddenly from normal operation. During investigation, motor shaft was found running freely. No movement was seen on cooler fan. Coupling between motor to gearbox was inspected. Coupling is shear plate coupling. Its spacer flexible element were found broken into several pieces. Further investigation revealed that motor coupling hub was moving free axially back and forth due to clearance between motor shaft to coupling hub internal diameter. Motor side Coupling hub bolt hole was found with loss of material and ovality in shape. Hub locking Allen screw was found in damaged condition. Missing materials were noted and broken shear plate materials were found around coupling guard area. While site team was conducting the investigation on the unit A, similar incident occurred in next unit and other 3 units with 2 days difference between them. During detailed investigation it has been noted that all motor to gear box coupling are shear plates and shear plates were broken. Coupling hub was found loose and coupling hub locking screw was found broken or partial damage.

COMPARISON OF THREE PREDICTIVE ANALYSIS METHODS FOR WIND TURBINE GEAR BOXES. A CASE STUDY OF SATELLITE BEARING WEAR AND GEAR TEETH SURFACE DAMAGES

The aim of this paper is to review and compare diverse predictive analysis methods used for the inspection of the internal conditions of wind generator gear box bearings on wind turbines in order to determine the accuracy, deficiencies, and validity of these methods. Thus, three different types of predictive analysis will be compared: visual analysis using boroscopy (that is an industrial type of endoscopy), oil analysis, and bearing condition unit vibrations analysis. These analyses were carried out on a ten-year-old wind farm that has forty-eight 800 kW wind turbines; the results will allow other similar wind farms to determine the most appropriate predictive strategies. In the studied gear boxes, damage is restricted to the bearings of the satellites. Therefore, the study has focused on this part of the gear box. The study demonstrates that bearing condition unit vibration analysis can predict severe damage in all cases, so it is possible to predict bearing failure within 6 months; as a result, it is possible to establish the optimal moment to substitute bearings to avoid catastrophic failure in gear boxes. In addition, given that a boroscopy can detect all types of damage in the bearings of the satellite and thus can predict failure ahead of 6 months as well as detect low and moderate damage, it becomes the method of preference. Keywords: wind, turbine, gear box, bearing, predictive analysis

Development of a Novel Sensor for Gear Teeth Wear and Damage Detection

Health monitoring of mechanical transmission systems is an important area of research. Mechanical transmission systems, especially gear boxes in aircraft, automobiles, and wind turbines etc. account for many of the maintenance costs due to repairs, replacements and downtime. Gear boxes can experience high level of failure due to varied load conditions and harsh environments. Replacing the gear box is quite an expensive process and has significant downtime. Current gear box monitoring involves mainly measuring vibrations, however vibrations occur when the fault in the gear has already progressed significantly. Gear teeth monitoring lacks sensor technology to successfully detect tooth damage and misalignment. This paper presents a new concept gear teeth damage detection using eddy current sensors fitted on to the teeth of an idler gear at various locations. These sensors detect various faults encountered in a gear such as micro and macro pitting of the tooth surface, contact wear etc. Eddy current sensors are already being used to detect turbomachinery blade vibrations and tip clearance as they are robust and immune to contamination. In the present case, we use an idler gear that incorporates miniature eddy current sensors and state of the art electronics with wireless data transmission to enable the device to operate remotely and in harsh environments. A rotating rig with gears (spur and helical) and oil supply was built to test and validate the sensor by seeding various faults on the tooth surface. The results show that the idler sensor gear was able to detect various faults. The new eddy current sensor idler gear concept will enable health monitoring of the gearbox and ensure timely maintenance and reduction in operation costs.