Overload protection systems and mechanics of machines Essay

Overload protection systems and mechanics of machines - Essay Example Overload protection systems play a great role in protecting people and equipment from harm that may result from such faults or overloads. Overload protection systems normally feature overload switches or relays that serve to cut off power supplies to certain elements of the system and, therefore, prevent the machine from working normally (Gurevich 2003, p. 57). There are different overload protection systems that exist, each with its specific function and application. In industries that involve the movement of heavy loads, overload protection systems are installed to ensure that the machine, equipment and people are protected against injustices or damages that may occur in case the machine is loaded beyond its capacity (Gurevich 2003, p. 183). Systems that protect against weight overload commonly exist on cranes and elevators. There are also machines that work in environments that feature a lot of heat. Some machines are installed with protection systems to prevent them from damage b y extreme heat or cold. These systems are fitted with sensors that prevent them from functioning normally under adverse thermal conditions. One example of an overload protection system used in cranes is the LKV Crane Overload Guard. Figures 1 and 2 show the LKV Crane Overload Guard. Fig. 1 & 2: LKV Crane Overload Guard Courtesy of www.unirope.com The guard is attached to a line part that is stationary. The guard is installed such that the wire is deflected slightly between the clamping jaw and the two wheels (Unirope 2013, par. 3). The rope tends to straighten when the system is subjected to a load. When this happens, a force is applied to the clamping jaw as well as to the pull rod. If the load exceeds a present switch value, the pull rod activates a microswitch which closes or opens a circuit (Unirope 2013, par. 3). The load cell contains a spring element that is preloaded to reduce the movement by the pull rod to about a quarter of the full load. Many machines that are used in in dustries rely on electrical energy for their control or functioning. Electricity supplies sometimes fluctuate to the extent of transmitting currents beyond the ratings of machines or their components. To prevent electrical and electronic systems from damages that result from too much, too low or fluctuating currents or voltages, some machines are fitted with overload switches (Gurevich 2003, p. 124). Scientific Principles of Mechanics of Machines A machine is basically a tool or equipment that makes work easier and faster. Machines commonly use electrical, chemical, thermal, or mechanical energy to meet the objectives for which they are intended. Many machines that are used today are complex in nature and often times comprise one or more simple machines and computer systems. Simple machines include levers, pulleys, wheels and axels, inclined planes, screws, and wedges. Mechanical Advantage Machines are specifically designed to make work easier and faster. The level to which a machin e makes work faster or easier is known as the mechanical advantage (MA). In Engineering and physics, mechanical advantage is defined as the number of times a machine multiplies the effort implied into it (ThinkQuest 2013, par. 1). In other words, it is the ratio of exerted working force produced by a machine to the effort applied, the units of force being measured in Newtons. In order to determine the mechanical advantage of a machine, one needs to divide the resistance force by the force of effort (ThinkQuest 2013, par. 1). In many cases, the resistance force is equal to the weight of the object. Mechanical Advantage of Pulley Systems A pulley is basically a machine that comprises a wheel that has a groove. A cable, belt or rope runs inside the groove to lift or lower loads and to