Difference between Star and Delta Connection

This article covers the key differences between star and delta connection on the basis of several important factors such as their configuration, voltage, current, power, motor speed, neutral point, number of turns, insulation level, and applications. In Delta connection, phase sides are connected in a cyclical arrangement in order to …

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Difference between Intrinsic and Extrinsic Semiconductor

This article covers the key differences between intrinsic and extrinsic semiconductor materials on the basis of purity, conductivity, uses, energy gap, temperature, and examples. An intrinsic semiconductor is the one which is made of the extremely pure semiconductor material. They have the equal number of holes and electrons so do …

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Difference between induction motor and synchronous motor

Difference-Between-Induction-Motor-and-Synchronous-Motor-Induction_motors

This article covers the key differences between the induction motor and synchronous motor on the basis of several important factors such as Construction, Starting Mechanism, Excitation, Speed Control, Power Factor, Load Change, Cost, Slip, Efficiency, and Applications. The induction motor is the most common type of AC motor. It is …

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Power in an AC Circuit

Instantaneous Power

In an alternating-current circuit, power is dissipated in a resistor, but not in a pure inductor or a capacitor. Because the current in an RL circuit lags the supply voltage by an angle ϕ, the amount of useful power supplied to the circuit is proportional to Cosϕ. Similarly, in an …

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Latches and Flip Flops

The goal of this module is to explore Sequential Logic and its functional building blocks and to describe the operations of latches and flip-flops in digital circuits. Objective A learner will be able to: Explain the difference between combinatorial logic and sequential logic. Define positive and negative edge triggering. Explain …

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Logic Simplification Karnaugh map

3 variable k map

The goal of this module is to provide learners with tools for reducing Boolean algebra expressions to their simplest form. Objectives The learner will be able to: Reduce Boolean expressions using the 14 Boolean rules. Simplify complex Boolean algebra expressions using the 14 Boolean rules and apply DeMorgan’s Theorem. Carry …

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Basic Logic Gates and Boolean expressions

The goal of this module is to enable learners to apply basic logic gates and Boolean expressions to digital circuits. Objectives A learner will be able to: Explain the difference between analog and digital quantities Give examples of binary numbers and describe their structure Give examples of hexadecimal and octal …

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Number Systems in Digital Electronics

The goal of this module is to provide learners with skills and practice necessary to enable them to convert between number systems used in digital electronics. Objective The learner will be able to Explain the difference between analog and digital quantities Give examples of binary numbers describe their structure Give …

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Buck-Boost Transformer Working Principle

An isolation transformer can be wired as an autotransformer in a buck configuration

A buck-boost transformer is a type of transformer which is primarily used to adjust the voltage level applied to various electric equipment. Buck-boost transformers are utilized in in several applications such as uninterruptible power supplies (UPS) units for computers. When an existing AC electrical circuit suffers from excessive voltage drop …

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Starting Methods of Three Phase Induction Motor

Results of Y-Delta motor start

Three-phase Induction motors draw six or more times rated current when started at rated voltage. Such high currents may pose serious problems for the motor and the electrical system when large motors are started. One way to reduce the starting current is to start the motor at reduced voltage. After …

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Three Phase Induction Motor Performance

Characteristic curves of an induction motor

Using the equivalent circuit of the three-phase induction motor and some additional information about the mechanical and core loses, one could calculate the performance of the three-phase induction motor from no-load to full-load. Figure 1 shows a set of generic curves of efficiency, current, power factor, and slip for an …

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Torque Speed Characteristics of Induction Motor

Induction motor torque-speed characteristic 2

Figure 1 showed a plot of induction motor torque vs speed from zero to synchronous speed. This curve is called the torque-speed characteristic curve. We can derive an equation from the equivalent circuit that allows the calculation of the torque for a given value of slip. FIGURE 1    Induction motor …

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Three-Phase Induction Motor Efficiency

Power flow diagram for an induction motor

The equivalent circuit of the induction motor can be used to examine the losses and the efficiency of the machine. Efficiency is defined for an induction motor the same way as it is for any device: \[\begin{matrix}   \eta =\frac{Power\text{ }Out}{Power\text{ }In}=\frac{{{P}_{out}}}{{{P}_{in}}} & {} & \left( 1 \right)  \\\end{matrix}\] Defining the …

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Three Phase Induction Motor Equivalent Circuit

Per-phase induction motor equivalent circuit

The three-phase induction motor operates in some ways like a transformer. In the transformer, AC voltage is applied to the primary, which creates AC flux in the core. That flux links the secondary and induces a voltage of the same frequency, but with a voltage that depends on the transformer …

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