Self Study World

Current Collector A current collector is a device used to collect electrical current from a moving conductor, such as a train or a trolley. It is typically used in electric vehicles, such as trains and trams, to transfer power from an overhead power source to the vehicle's electric motor. The current collector consists of a sliding contact, which is often made of carbon or copper, that makes contact with an overhead power source, such as an overhead catenary wire or a third rail. The sliding contact is mounted on the vehicle and is typically in the form of a pantograph or a trolley pole. The pantograph is a device with a metal frame and a spring-loaded arm that presses against the overhead power source. It is raised and lowered by the operator of the vehicle, and as it moves along the overhead power source it maintains contact and collects the electrical current. The trolley pole is a vertical pole that is mounted on the roof of the vehicle and has a horizontal arm that extends out

Suspension Definition and Properties The substance of little size particles that are insoluble in the solvent, but which are visible distinctly through the naked eye is called a suspension . Thus it is a heterogeneous mixture of two or more substances and in it, the sizes of the dispersed particles are of the order of 10-5 cm or more. The little particles can be filtered and these are temporary which have a common tendency to scatter from the medium of dispersion. There are so many examples of suspension in our common walk of life like the water of the river, smoke in atmospheric air, etc. Properties of Suspension The suspension is a heterogeneous mixture. The particles of suspension can be seen by the naked eye and its size is of the order of 10-5 cm or more. The particles of suspension scatter a beam of light passing through it and make its path transparent (visible). The suspension is unstable because the solute particles settle down when it is left undistributed. That'

SF6 Sulfur Hexafluoride Circuit Breaker SF6 Circuit Breakers Is a Circuit Breaker whose Excellent insulating, arc-extinguishing, and physical and chemical properties of SF6 gas are the greater advantages of SF6 circuit breakers. The gas is noninflammable and chemically stable. SF6 Circuit Breaker Diagram What is SF6 Gas The gas costs less if manufactured on a large scale.  The gas is transported in liquid form in cylinders. Before filling the gas, the circuit breaker is evacuated  40 the pressure of about 4 mm of mercury so as to remove the moisture and air.  The gas can be reclaimed by the gas handling tank. The sulfur hexafluoride possesses very good insulating properties and outstanding arc-quenching Thametcristics which make it an ideal medium for circuit inscription. The physical, chemical, and dielectric properties and are-quenching characteristics of SF6 gas are given below: It is colorless, odorless, non-toxic, and noninflammable gas. This gas is extremely stable an

Constant Mesh In this type of gearbox, all the gears are in constant mesh with the corresponding gears on the layshaft. The gears on the most shaft that is splined, are free (fig). The dog clutches are provided which are free to slide on the main shaft. The gears on the layshaft. are, however, fixed. When the left dog clutch is slide to the left by means that of the selector mechanism, its teeth area unit engaged with those on the clutch gear and that we get the direct gear. The same dog clutch, however, once slide to right makes contact with the gear and gear is obtained. Similarly movement of the right dog clutch to the left results in low gear and towards the right in reverse gear. Double declutching the constant mesh box, for the smooth engagement of the dog, clutches it's necessary that the speed of the main shaft gear and therefore the sliding dog should be equal. Therefore to get lower gear, the speed of the clutch shaft, layshaft, and main shaft gear must be increased. This

Berry Type Transformer Berry type transformer is like Shell type transformer, just they have a conveyed attractive circuit. This center development is like the spokes of a wheel. The quantity of the attractive transition way is more than 2.   It is commonly kept in firmly fitted sheet metal tanks. The tanks are built of explicit top-notch steel plate cut shaped and welded into the unbending structures. Every one of the joints is painted with an answer of light blue chalk which turns dull within the sight of oil, revealing even the minutest breaks. The tanks are loaded up with the unique protecting oil. The whole transformer gets together is submerged in the oil. The oil served two capacities. keep the loops cool by flow Gives the transformers an extra protection

Free Wheel Unit Free Wheel Unit In some vehicles a freewheel unit (also called freewheel clutch) is provided just after the gearbox. Fig. shows the construction of this unit. It is very much similar in action to the bicycle freewheel. The inner driving mem her is connected to the gearbox shaft and the outer one to the propeller shaft. The driving member has the three steps as shown in fig. In each step, there are 3 spring-mounted rollers of various sizes. When the driving member is rotating in the direction shown in the fig. the driven member will also be rotating in the same direction. But when the driven member becomes the driving member e.g., when the car is going downhill with the engine stopped or clutch disengaged, the inner member will not rotate along with the outer one. Thus, during this case, the transmission and the engine will be isolated from the wheels. This results in fuel economy. In some instances, the freewheel has to be locked, e.g. in the reverse drive. In such case

Prony Brake Dynamometer The simplest form of absorption type dynamometer is a pony brake dynamometer, as shown in Fig. It consists of two wooden locks placed around a pulley fixed to the shaft of an engine whose power is required to be measured. Prony Brake Dynamometer Diagram A turbinate spring is provided between the nut and also the higher block to regulate the pressure on the pulley and regulate its speed. The higher block has a long lever connected to it and carries a weight of W at its outer finish. A counterweight is placed at the other end of the lever which balances the brake ' when unloaded. Two stops S, S are provided to limit the motion of the lever. When the brake is to be put in operation, the long end of the lever is loaded with suitable weight W and the nuts are tightened until the engine shaft runs at a constant speed and the lever is in a horizontal position. Under these conditions, the moment due to the weight W must balance the moment of the frictional resistanc