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Applications of DC Motors

  Applications of DC Motors The applications of different types of DC motors are given below  Series DC Motor Series DC motors are used in applications where high starting torque is required. Series DC motors are used in cranes and hoists. Series DC motors are used in electric tractions. They are used in air compressors. They are also used in vacuum cleaners. Series DC motors are also used in sewing machines, etc. Shunt DC Motor Shunt DC motors are used in applications that require constant speed. Shunt DC motors are used for driving lathe machines. These are also used in centrifugal pumps and blowers. These are used in fans, conveyors, and spinning machines. These DC motors are also used in lifts. Compound DC Motor Compound DC motors are used in those applications which require high starting torque and constant speed. Used in printing presses. They are also used in shears. They are used in elevators and lifts. Compound DC motors are also used in rolling mills and heavy planners, etc.

Through-Hole vs. Surface Mount

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  In recent years, semiconductor packaging has evolved with an increased demand for greater functionality, smaller size, and added utility. A modern PCBA design has two main methods for mounting components onto a PCB:  Through-Hole Mounting  and  Surface Mounting.   Through-Hole Mounting (THM): Through-hole mounting is the process by which component leads are placed into drilled holes on a bare PCB. The process was standard practice until the rise of surface mount technology (SMT) in the 1980s, at which time it was expected to completely phase out through-hole. Yet, despite a severe drop in popularity over the years, through-hole technology has proven resilient in the age of SMT, offering a number of advantages and niche applications: namely, reliability.   Through-hole components are best used for high-reliability products that require stronger connections between layers. Whereas SMT components are secured only by solder on the surface of the board, through-hole component leads run th

SPECIAL FUNCTION REGISTER IN 8051

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  SPECIAL FUNCTION REGISTER (SRF) OF 8051 MICROCONTROLLER To monitors or control the various functions within a microcontroller like control different hardware peripherals like Timers, Serial Port, I/O Ports etc. Here we use some special registers in 8051 microcontroller called  Special Function Register (SRF)  (or Special Purpose Register, or simply Special Register). If we want to assess or change the operating mode of the 8051 Microcontroller. This will be done by manipulating the 8051 Microcontroller  Special Function Registers (SFRs). In 8051 micro controller there are  21 Special function registers (SFR)  and this includes Register A, Register B, Processor Status Word (PSW), PCON etc.  So, it required 21 unique locations for these 21 special function registers and the size of each register is of 1 byte. Some of these special function registers are  bit addressable   registers  (which means you can access 8 individual bits inside a single byte), while some others are  only byte ad

Universal Motor

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  What Is a Universal Motor? A universal motor is a special type of motor that runs on both AC and DC power supplies. Universal motors are series-wound (the armature and field windings are in series). The series connection allows them to generate high torque; hence the universal motors are generally built into the device they are meant to drive. Most of the universal motors are meant to operate at speeds as high as 3500 RPM. These motors run at a higher speed on DC supply than they run on AC supply of the same voltage. This is due to the reactance voltage drop that is present only in AC and not in DC. How does a Universal Motor run on both AC and DC supply? The construction of a universal motor is similar to that of a  series-wound DC motor . A universal motor incorporates some modification that allows it to operate either on AC or DC supply. Construction of a Universal Motor A universal motor consists of a stator on which the field poles are mounted. Field coils are wound around the f

Corona Effect

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  Corona Effect in Overhead Transmission Line The 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 voltage, the larger and higher the luminous envelope becomes and the higher are the power loss and the radio interference.  If the applied voltage attained the breakdown value, then a flashover will occur between the conductors due to breakdown of the insulation of air. If the transmission conductors are polished and smooth, then the violet gl

OVERVIEW OF 8051 FAMILY

  Comparison of 8051 with its other family members Introduction : 8051  is 8-bit microcontroller with 4 KB program memory and 128 Bytes data memory. Other features include four 8-bit ports, two 16-bit timers and one on-chip serial port.  Overview of the 8051 Family :  8051 microcontroller was initially designed by Intel Corporation in 1981. Features of 8051 made it extremely popular in market. Because of it’s popularity and high demand Intel allowed other manufacturers to fabricate and market different variants of 8051 with a condition that all these variants should be code compatible with 8051. This resulted in a lot of variants of 8051 in market, among which 8052 and 8031 are the most popular ones. Therefore, 8052 and 8031 are considered as the family members of 8051. 8052 –  8052 is the super set of 8051 as it has all the features of 8051 with an extra timer and an extra RAM of 128 bytes. Therefore, 8052 has a total of 256 bytes of RAM and 3 timers in all. Also all the programs writ

DOL Starter

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Working of DOL Starter  The wiring connection of DOL starter with start and stop buttons is shown in figure below. The DOL starter main terminals are connected between the mains supply terminals and motor terminals while the control circuit is energized with two terminals of three phase supply as illustrated in figure When the start button is pressed, current will flow through one phase to the control circuit and the contactor coil to the other phase. This current energizes the contactor coil which makes to close the contacts thereby three phase supply is connected to the motor. Since the start button is of pushbutton, when it is released the control circuit still maintains the supply through hold-on contact. If the stop button is pressed or overload relay coil operate, the current path through contactor coil will break and hence the contactor contacts drops out, thus breaking the supply to the motor. Once the power supply is interrupted, again the supply to the motor is established by