Study of Belt Drive Lab Report Example | Topics and Well Written Essays - 2000 words

Study of Belt Drive - Lab Report Example Though gears are more efficient, they can only work with fixed gear ratios. Various in case of belts they can work with continuously varying sizes of the pulleys, thus enabling usage at all levels. Belts are used in applications in the kitchen grinders to cars. While belts can transmit power, they are generally considered inefficient because of the slip between the pulley and the belt. This also results in ineffective transmission ratio and hence the speed. The slip of a belt depends on the coefficient of friction between the two, the shape of the belt and the torque transmitted. Belts used can be flat belts which are supposed to have a higher slip compared the vee belts. Originally, belts were made of leather and rubber but today a number of synthetic materials and steel based belts are available that reduce the wear and tear. The relationship between the tensions in the slipping pulley is studied and recorded by Grosjean1 and Fawcett and Burdes2 using the apparatus shown in the figure 1. The details are shown in the calculations below: 1. The motor voltage is set at 10V and the angle of contact between the pulley and the string is made 90 degrees. The pulley direction is maintained such that the weight tension is more than the spring tension at the spring balance end. The theoretical values and the experimental values do not tally. ... 3. Apparatus The experiment has the following apparatus in place as shown in figure 1. 1. There is a variable speed DC electric motor driving pulley of a fixed radius. 2. The pulley has on one end a series of weights which is variable from 0 N to 10 N. 3. On the other end, the string running over the pulley supports a spring balance which helps in measuring the tension on the other side. 4. The angle of contact between the pulley and the string can be set to four different values 5. The motor voltage and current is measured using digital meters and the rotational speed of the pulley is measured using a digital tachometer. 4. Procedure The following procedure is followed during the experiment: 1. The motor voltage is set at 10V and the angle of contact between the pulley and the string is made 90 degrees. The pulley direction is maintained such that the weight tension is more than the spring tension at the spring balance end. 2. Load T2 is varied by hanging a range of weights on the string. For each weight the string tension along the spring balance is measured and recorded. 3. The load is varied until the motor stalls and the red current control light starts flickering. 4. This operation is repeated for various string contact angles of 180, 270 and 360 degrees. 5. For one contact angle alone, in addition to measuring the tensions, the pulley speed, the voltages and the current at the motor end are also measured and recorded. 5. Results The results of the above experiment are recorded below: Belt Drive Results 90degrees T2 T1 Voltage (V) Current (A) Motor Speed (rpm) Motor Speed

Project Scope, Time, Cost, and Quality Essay Example | Topics and Well Written Essays - 500 words

Project Scope, Time, Cost, and Quality - Essay Example In level one of the maturity model, the processes are ad hoc and chaotic. The project is completed and results are obtained but the success is not repeatable since much is attributed to the skills of the resources involved. Also often the project exceeds limits of time and budget and critical processes are overlooked to get the work done. To move from this level to the next, definite practices need to be put in place and the company should only accept projects that can be executed within its infrastructure. In level two, some project management practices are in place and hence the results are repeatable. Also processes are adhered to even when time is critical and results are documented for future use. Process discipline and project specific standards helps in this level, but to move on to the next level, organization-wide fixed standards are essential, and they allow for project specific versions as a deviation. Requirement Management, Project Planning, Tracking and Oversight, Quali ty Assurance and Configuration Management are introduced at a project specific level.In maturity level three, the process is now tailored for every aspect of the project. The measuring tools, standards and methodology are in place and the management has knowledge of the project status at all times. The key feature is that there is consistency in the processes and project quality is assured. To move on to the next level, statistical analysis will go a long way to predict performances accurately. Level 2 Quality management and processes are defined and managed at an organization level instead of at a project level. PMMM Level 4 Managed In maturity level four, the measurements of the project management processes are very well defined and precise: statistical techniques are employed for even the sub processes as they are considered to impact the overall performance. The processes are maintained even when modifications are needed due to project uniqueness. The projects can now be quantitatively predicted as compared to the qualitative predictions in level three. Software Quality Management and Quality Process Management are introduced at this level. PMMM Level 5 Optimized In maturity level five, continuous self-improvement processes are