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To merge dataframes of different length, we need to use the merge() method. Let’s say the following is our 1st DataFrame with length 4 −dataFrame1 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Jaguar'] } ) print("DataFrame1 ...", dataFrame1) print("DataFrame1 length = ", len(dataFrame1))Following is our 2nd DataFrame with length 6 −dataFrame2 = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Mercedes', 'Jaguar', 'Bentley'] } ) print("DataFrame2 ...", dataFrame2) print("DataFrame2 length = ", len(dataFrame2))Now, merge DataFrames using the merge() −mergedRes = dataFrame2.merge(dataFrame1, how='left')ExampleFollowing is the code −import pandas as pd # ... Read More
The choice of operating frequency for electric heating is a significant factor for heating because it greatly affects the work to be heated and the method of its heating, whether dielectric heating or induction heating.In practice, the furnaces operating on power frequency of 50 Hz can be of 1 MW capacity, those operating on medium frequencies (about 500 Hz to 1000 Hz) have a capacity of 50 kW and those operating on high frequencies (about 1 MHz to 5 MHz) have capacities ranging from 200 kW to 500 kW.Therefore, the factors which are considered while selecting the frequency for electric ... Read More
Transmission Line SupportsThe supporting structures used for overhead transmission line conductors, such as poles and towers, are called the transmission line supports.Generally, the transmission line supports supposed to possess the following properties −The line supports should have high mechanical strength so that it can withstand the weight of conductors and wind loads, etc.It should be light in weight without the loss of its mechanical strength.It should have longer life.It should be cheap in cost and economical to maintain.Accessibility of line conductors for maintenance is to be easy.There are various types of line supports available. The choice of supporting structure for ... Read More
What is Electric Supply System?The carrier of electrical power from power generating station to the consumer’s premises for its utilisation is called the electrical supply system.The whole electric supply system is segmented into three principle components, viz. −Power generating stationTransmission systemDistribution systemThe electric power is produced at the power generating station which are located quite away from the consumers. Then, the power is transmitted over large distances to load centres with the help of conductors called transmission lines. Finally, it is distributed to a large number of consumers through a distribution system.Types of Electric Supply SystemDepending upon the types of ... Read More
The element of the transmission line by which the line conductors are insulated from supports is known as line insulator. The insulators used in the transmission lines are of various types. Some of the important types of insulators are given as follows −Pin Type InsulatorSuspension Type InsulatorStain InsulatorShackle InsulatorPin Type InsulatorsThe pin type insulator is shown in the figure. The pin type insulator is fitted to the cross-arm on the pole. The pin type insulator has a groove on the upper end of the insulator for housing the line conductor. The line conductor passes through this groove and is bounded ... Read More
Corona Effect in Overhead Transmission LineThe phenomenon of violet glow, hissing sound and production of ozone gas in an overhead transmission line is known as corona.When a very high voltage is applied across two conductors of the overhead transmission line whose spacing is large as compared to their diameters. When this applied voltage exceeds a certain value (called critical disruptive voltage), then the conductors are surrounded by a faint violet glow that is known as corona effect.In practice, the corona effect is accompanied by a hissing sound, production of ozone, power loss and radio interference. The higher is the transmission ... Read More
What are Insulators?Insulators are the elements of transmission system which provide necessary insulation between line conductors and supports and hence, prevent any leakage current from the conductors to the earth.The line conductors in the overhead transmission lines should be supported on the poles or towers in such a way that the current from the conductors do not flow to the earth through the supports which means the line conductors must be properly insulated from the supports. This is achieved by using the insulators between the line support and conductors.The commonly used material for manufacturing the insulators of overhead transmission line ... Read More
The transmission voltage for which the cost of conductors, transformers, insulators, switchgears and other terminal apparatus is minimum is called the economical transmission voltage.As we know, if the transmission voltage is increased, the volume of conductor material required for the transmission lines is reduced. Hence, this decreases the expenditure on the conductor material. It is advisable to use the highest possible transmission voltage in order to reduce the expenditure on the conductor material to a minimum. Although, it may be remembered that as the transmission voltage is increased the cost of insulation, transformers, switchgears and other terminal equipment also increases. ... Read More
Underground Electric Transmission SystemThe system of electric power transmission uses underground cables for transmitting the electric power from the generating station to the consumers is known as underground electric transmission system.Underground cables have low visibility and are not affected by bad weather. However, the cost of these cables is comparatively high and their laying process is also time consuming.Types of Underground Transmission SystemBased on the type of supply (i.e. AC or DC) and the number of conductors used, the underground electric transmission system can be classified into the following types −Underground DC SystemTwo-Wire DC SystemTwo-Wire DC System with Mid-Point EarthedThree-Wire ... Read More
AC (Alternating Current) and DC (Direct Current) are the two different types of electric current that are used in the welding process. AC arc welding is commonly used for down-hand heavy plate welds, fast fills and with aluminium TIG welding with high frequency, while DC welding is better for welding thinner metals. Also, the equipment used for DC arc welding are also cheaper than AC arc welding machinery.The specifications of equipment used in practice for AC and DC arc welding are given as follows −Specifications of AC Arc Welding Machinery - AC transformer − Step down, oil cooled, 3-phase, 50 ... Read More