RAKESH SINGH BADAL IFTM UNIVERSITY

Ptotal Qtotal (5) For example: 1. P1 = -80 Watts P2 = 127 Watts | Ptotal | = 47.0 Watts | Qtotal | = 358.5 VARS | θ | = tan –1                                     | 47 | | 358.5 | = 82.53o       2 . P1 = 127 Watts P2 = -80 Watts | Ptotal | = 47.0 Watts | Qtotal | = 207.0 VARS | θ | = tan –1 | 47 | | 207 | = 77.21o

In a three phase, wye or delta three wire system, under balanced or unbalanced conditions, with any power factor, the two-wattmeter method is a practical and commonly used method of measuring total three phase power. A simplified circuit diagram of the two-wattmeter connections is shown in Fig.1. Figure1 is simplified in the sense that the ammeters, current transformers, selection switch, and polarity switch have been omitted. The polarities of the voltage and current connections to the wattmeters are significant. Note that the line in which the current is not measured, line “c”, is connected to the negative voltage terminal on both wattmeters. Figure 1: Connections for the two-wattmeter method. Notice that this is a three-wire system. The total power delivered to the load is given by Eq.1. P total = P 1 + P 2 (1) As indicated in Fig.1, each wattmeter measures a line current and a line to line voltage. The wattmeter reading indicates the product of line c

• • Sometimes cells may not be formed because of inadequate part families. • Some cells may have a high volume of production and others very low. This results in poorly balanced cells. • When volume of production changes, number of workers are adjusted and workers are reassigned to various cells. To cope with this type of reassignments, workers must be multi-skilled and cross-trained. • Sometimes, machines are duplicated in different cells. This increases capital investment.

• Reduced material handling and transit time • Reduced setup time • Reduced work-in-process inventory • Better use of human resources • Better scheduling, easier to control and automate

• Every cell contains a group of machines which are dedicated to the production of a family of parts. • One of the problems is to identify a family parts that require the same group of machines. • These layouts are also called as group technology layouts. • • The previous slide shows a facility in which three parts A, B, C flow through the machines. • The next slide provides the information in a matrix form which includes some other parts D, E, F, G, H. • The rows correspond to the parts and columns to the machines. • Just by interchanging rows and columns, eventually a matrix is obtained where the “X” marks are all concentrated near the diagonal. This matrix provides the cells. For example, parts A, D and F require Machines 1, 2, 4, 8 and 10 which forms a cell.

• A process layout is a functional grouping of machines. For example, a group of lathe machines are arranged in one area, drill machines in another area, grinding machines in another area and so on. Different job jumps from one area to another differently. Hence, the flow of jobs is difficult to perceive. This type of layout is suitable for a make-to-order or an assemble- to-order production environment, as in a job shop where customization is high, demand fluctuates, and volume of production low. Since a wide variety of products are produced, general purpose equipments and workers with varied skills are needed. • A product layout arrangement of machines. Every job visits the machines in the same order. This type of layout is suitable for a make-to-stock or an assemble-to-stock production environment, as in a flow shop where products are standard, demand stable, and volume of production high. Since variety is low, special purpose equipments and workers with a limited skil

• Process Layout •   Used in a job shop for a low volume, customized products • Product Layout –   Used in a flow shop for a high volume, standard products • Fixed Position Layout –   Used in projects for large products e.g., airplanes, ships and rockets • Cellular layouts –   A cell contains a group of machines dedicated for a group of similar parts –   Suitable for producing a wide variety parts in moderate volume

• Facilitate •   organization structure –   communication and interaction between workers –   manufacturing process –   visual control • Minimize –   manufacturing cycle time or customer flow time –   investment • Provide –   convenience, safety and comfort of the employees –   flexibility to adapt to changing conditions • A facility layout problem may have many objectives.  In the context of manufacturing plants, minimizing material handling costs is the most common one. • Other objectives include efficient utilization of –   space –   labor • Eliminate –   bottlenecks –   waste or redundant movement

It is the name given to the most common tool steel. As the name implies, it can cut steel at high cutting speeds. These steels are high in alloy content, have excellent hardenability, maintain their hardness at elevated temperatures around 650°C, are quite resistant to wear and contain relatively large amounts of tungsten or molybdenum, together with chromium, cobalt or vanadium. They are used to produce cutting tools to be operated for various machining operations such as turning, drilling, milling, etc. A typical composition of H.S.S. is tungsten 18%, chromium 4% and vanadium 1%, carbon 0.75 to 0.9% and rest iron.

Diffraction effect can be observed only if the spacing between the lines. The grating is of the order of magnitude of the wavelength of light used. The grating element is of the order of 10 -6   m. The wavelength of x-ray is of the order of 1/1000 th   of the wavelength of visible light. The grating should have a spacing 1/1000 th   of the grating used in the visible region. Von Laue suggested that the crystal can be used for the diffraction of X-rays because the spacing between the atoms of a crystal are of the order 1Å.

Moulding sand properties and its classification: The moulding is a process of making a cavity or mould out of sand by means of a pattern. The molten metal is poured into the moulds to produce casting. Properties of moulding sand 1: porosity or permeability It is the property of sand which permits the steam and other gases to pass through the sand mould. The porosity of sand depends upon its grain size, grain shape, moisture and clay components are the moulding sand. If the sand is too fine, the porosity will be low. 2: Plasticity It is that property of sand due to which it flows to all portions of the moulding box or flask. The sand must have sufficient plasticity to produce a good mould. 3: Adhesiveness It is that properties of sand due to it adheres or cling to the sides of the moulding box. 4: Cohesiveness It is the property of sand due to which the sand grains stick together during ramming. It is defined as the strength of the moulding sand. 5: Refracto

Moulding sand properties and its classification: The moulding is a process of making a cavity or mould out of sand by means of a pattern. The molten metal is poured into the moulds to produce casting. Properties of moulding sand 1: porosity or permeability It is the property of sand which permits the steam and other gases to pass through the sand mould. The porosity of sand depends upon its grain size, grain shape, moisture and clay components are the moulding sand. If the sand is too fine, the porosity will be low. 2: Plasticity It is that property of sand due to which it flows to all portions of the moulding box or flask. The sand must have sufficient plasticity to produce a good mould. 3: Adhesiveness It is that properties of sand due to it adheres or cling to the sides of the moulding box. 4: Cohesiveness It is the property of sand due to which the sand grains stick together during ramming. It is defined as the strength of the moulding sand. 5: Refracto

Moulding sand properties and its classification: The moulding is a process of making a cavity or mould out of sand by means of a pattern. The molten metal is poured into the moulds to produce casting. Properties of moulding sand 1: porosity or permeability It is the property of sand which permits the steam and other gases to pass through the sand mould. The porosity of sand depends upon its grain size, grain shape, moisture and clay components are the moulding sand. If the sand is too fine, the porosity will be low. 2: Plasticity It is that property of sand due to which it flows to all portions of the moulding box or flask. The sand must have sufficient plasticity to produce a good mould. 3: Adhesiveness It is that properties of sand due to it adheres or cling to the sides of the moulding box. 4: Cohesiveness It is the property of sand due to which the sand grains stick together during ramming. It is defined as the strength of the moulding sand. 5: Refracto