2016-08-17 14:39
There is a wide range of motors in existence for various purposes. However, the fundamental problems affecting the choice of motor protection are independent of the type of motor and the typ… Read More
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fault
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relay
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earth fault
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mho relay
bus zone protection
rotor earth fault
My Engineering Info provides the continuous Information's and Tutorials in the diversified field of engineering for Beginners, Students and Hobbyists.
2016-08-15 16:30
Mho Relay Construction and principle of OperationA simple form of Mho relay | Admittance or angle admittance relay shown in the figure below: It is an electromagnetic induction… Read More
2016-08-13 07:59
Need for Bus Zone ProtectionBusbar protection or bus zone protection includes, besides bus itself, the apparatus such as circuit breakers, disconnecting switches, instruments, transformers e… Read More
2016-08-12 04:38
Merz Price Protection of Power Transformer Merz price circulating current principle is commonly used for the protection of power transformer of 5MVA and and above against earth and phas… Read More
2016-08-07 16:09
Transformer ProtectionThe two major equipments in a power system are the generators and the power transformers. Faults occur less frequently on these apparatus, than on transmission li… Read More
2016-08-05 06:30
Rotor Earth Fault ProtectionAs the field is operated ungrounded, a single fault does not cause any flow of current or affect the operation of the electric generator. However, a single rotor… Read More
2016-08-04 04:52
Inter Turn Fault protection of StatorTurn to turn or inter turn fault on the same phase winding of the stator, can be never sensed by the percentage differential protection relay, which is o… Read More
2016-08-02 17:08
Phase to Earth Fault ProtectionPhase to earth faults normal occur in the armature slots. The ground fault current is usually limited by the resistance in the neutral of the generator. A sens… Read More
2016-08-01 21:25
Longitudinal or percentage or biased differential protection of stator (MERZ PRICE PROTECTION) The best form of stator protection against phase faults, occurring rarely, will be by different… Read More
2016-07-29 16:49
Static relays are mainly made with semiconductor switches like thyristor. In digital relays there are two states i.e., ON and OFF which can be referred to 1 and 0 state. Based on Characteris… Read More
2016-07-25 08:59
Protection of GeneratorsThe protections of generator are the most complex and elaborate due to the following reasons: Generator is a large machine, connected to bus-bars. It is a… Read More
2016-07-23 16:44
Comparator is a part of static relay, which receives two or more inputs to be compared and gives output based on the comparison. Types of ComparatorThe various types of comparators are; Amp… Read More
2016-07-22 17:13
Solid state relay or static relay is an electrical relay, in which the response is developed by electrical / magnetic / optical or other components without mechanical movement of components… Read More
2016-07-20 09:41
Under Frequency RelayFrequency based relays can either be under frequency relay or over frequency relay. The frequency relays are normally used in generator protection and for load-frequency… Read More
2016-07-17 03:37
Induction Type Reactance RelayA simplest form of electromagnetic induction type reactance relay (Induction Cup) is shown in the figure. The current is the operating quantity. It produces flu… Read More
2016-07-16 08:53
Distance protection | Impedance relay is a widely used protective scheme for the protection of high or an extra high voltage transmission lines. The operation of the conventional over curre… Read More
2016-07-14 09:42
This is also a special type of over current relay with a directional features. This directional over current relay employs the principle of actuation of the relay, when the fault current flo… Read More
2016-07-13 07:40
Operating Principles of Protective RelaysThe conventional types of electromagnetic relays (electro-mechanical relay) has one or more coils, movable elements, contact system etc and its opera… Read More
2016-07-10 13:26
Solid grounding Resistance grounding Reactance grounding Arc suppression coil or Peterson coil or resonant grounding Voltage transformer grounding Zig-zag transformer groundingElectric… Read More
2016-07-09 07:57
The study of unsymmetrical faults by symmetrical components method can be easily done by drawing sequence network in power system. A sequence network in a particular sequence current in a gi… Read More
2016-07-07 16:59
Consider a 3-phase system with an earth neutral system. Let a single line to ground fault occur on the red phase as shown in the fig below. It is clear from this figure that: The sequence cu… Read More
2016-07-06 17:48
Each elements of power system will present impedance to different phase sequence components of current which may not be the similar. For instance, the impedance which any part of equipment o… Read More
2016-07-06 08:19
In 1918, Dr.C.L. Fortescue, an American scientist, showed that the theory of symmetrical components for any unbalanced system of 3 phase currents or voltages may be regarded as being compose… Read More
2016-07-05 07:06
Class-A amplifier, which has centered Q point. Therefore the transistors operate only over the linear region of its load-line. So, it is an amplifier in which the circuit output current flow… Read More
2016-07-05 04:09
The two types of Faults are; Symmetrical Faults Unsymmetrical FaultsSymmetrical Types Of FaultsA three phase fault is commonly called as symmetrical fault. All the three lines are s… Read More
2016-07-01 17:17
An amplifiers system usually consists of several cascaded stages. Amplifiers are classified in many ways, according to their frequency range, the method of operation, the ultimate use, the t… Read More
2016-06-30 13:07
Introduction of Transistor Biasing Transistors are used in a large variety if applications in many different ways. Transistors can be used as a switch, a current source, linear circuit and a… Read More
2016-06-29 14:52
The full bridge rectifier is the most frequently used circuit for electronic DC power supplies. Generally we use AC device in many of the apparatus. We need AC source to operate those… Read More
2016-06-29 07:17
Rotating Machines Types of Duties and RatingsThe following are the types of duty as per I.S.4772 – 1968 “specification for “Electrical rotating Machines”. Rotating M… Read More
2016-06-27 14:25
IntroductionSince there are no rotating parts which induce a ventilating draught, transformers are more difficult to cool than rotating machines. For small outputs, up to, say,, 20KW, the e… Read More
2016-06-25 16:51
Consider n-p-n transistor in common collector configuration as shown in the figure. The base current IB is in input current and the emitter current IE is output current. The common collecto… Read More
2016-06-24 07:27
Principle Operation of Transistor (P-N-P)The basic connection of a p-n-p transistor is shown in the figure below. Let us consider the principle operation of transistor action at emitter-base… Read More
2016-06-23 16:45
Consider an n-p-n transistor in common emitter configuration. In this configuration the base current IB is the input current and collector current IC is the output current.We know IC =… Read More
2016-06-22 16:53
Consider a n-p-n transistor in common base configuration. In this common base configuration, emitter current IE is the input and collector current IC is the output current. Common Base Co… Read More
2016-06-21 17:04
When transistor used in practical circuits such as amplifiers, oscillators etc., we require four terminals, two for the input and two for the output port. Since the transistor has only thre… Read More
2016-06-20 14:13
Tra… Read More
2016-06-19 16:30
The figure above shows that the various transistor current components which flow across the forward biased emitter junction and the reverse biased collector junction. The emitter current IC… Read More
2016-06-18 18:33
Working Principle of P-N-P TransistorThe basic connection of a p-n-p transistor is shown in the figure below. Let us consider the action at the emitter-base junction of a transistor. It is f… Read More
2016-06-15 16:01
Transistor is one of the most important semiconductor devices. It was invented by William Shockey in the year 1947. The term transistor is derived by contracting the word transfer resistor… Read More
2016-06-14 09:50
Consider a portion of the transformer with the primary coil wound over the secondary, both the coils being cylindrical, as shown in the fig. The radial thickness of primary coil is bp and se… Read More
2016-06-13 09:59
A fuse can conduct continuously at maximum current without interrupting the circuit. Speed: The fuse blown speed depends upon the current flows through the circuit and type of material use… Read More
2016-05-26 17:01
A fuse can conduct continuously at maximum current without interrupting the circuit. Speed:The fuse blown speed depends upon the current flows through the circuit and type of material… Read More
2016-05-17 17:24
It stated that the laws governing the steady flow of electricity in a circuit may readily be modified. So as to be at once applicable to the magnetic circuit. ThusMagnetomotive Motive Force… Read More
2016-04-25 17:02
The abbreviation of HRC fuse is High Rupturing Capacity Cartridge fuse. It is one of the easiest forms of fuse which is used for the purpose of distribution. HRC fuse consist of a fuse wire… Read More
2016-04-19 04:12
A fuse can conduct continuously at maximum current without interrupting the circuit.Speed:The fuse blown speed depends upon the current flows through the circuit and type of material used to… Read More
2016-04-11 05:10
In engineering both electrical and electronics, a fuse is a form of low resistance resistors that acts as a sacrificial device to provide the protection from over current, of either the load… Read More
2016-04-09 09:03
Energy demand management may also name as demand side management (DSM). It is the alteration of consumers demand for energy during different methods such as economic incentives and education… Read More
2016-04-05 07:23
Statement: Any permutation of linear bilateral circuit elements and active sources, apart from the connections or complication, connected to a certain load RL possibly will replace… Read More
2016-03-13 14:39
This theorem is applicable for linear and bilateral networks. Let us see the statement of the theorem.Statement : In an any multisource complex network contains linear bilateral… Read More
2016-01-28 16:08
Kirchoff’s Current Law (KCL):Consider a junction point the figure shows the complex network. At this junction point if I1=2A, I2=4A and I3=1A then to find the current I4 we say, sum of… Read More
2015-11-08 07:30
The figure below shows the circuit diagram of a Full wave rectifier;The full wave rectifier contains diode D1 & D2. These diodes are connected in the centre tapped secondary coil of a tr… Read More
2015-04-19 07:43
Rectifiers: Electronics circuits need DC voltage for biasing. The commercial power supply for consumer is in the form of AC. Hence there is a need to convert AC voltage to DC voltage. A circ… Read More
2015-03-25 10:21
Properly doped crystal diode which has a piercing breakdown voltage is called as Zener diode. When the reverse bias on a PN junction crystal diode is enlarged, a critical voltage called as b… Read More
2015-03-08 16:19
PN Junction Voltage Ampere or VI characteristics of a PN junction are the curve between voltage across the junction and the circuit current. Usually, voltage is taken along X-axis and curren… Read More
2015-03-01 13:49
The potential difference across a PN junction can be applied in two ways. They are Forward BiasingReverse BiasingForward Biased PN Junction When an external voltage applied to the PN junctio… Read More
2015-02-18 06:06
We know that synchronous motor cannot start of its own. Hence some method must be used to start it. The starting of a synchronous motor from its standstill position can be obtained by the fo… Read More
2015-02-16 16:43
If a function is formed between a sample of P-type semiconductor and N type semiconductor, and this device called the PN junction or junction diode possess the properties of a rectifier. &nb&hell…Read More
2015-02-14 07:47
Semiconductors are classified into Intrinsic semiconductors and Extrinsic semiconductors. Extrinsic semiconductor further may be classified into N-type and P-type semiconductor. Intri… Read More
2015-02-12 14:47
The power factor of a synchronous motor is changed with a change in the excitation. When the excitation of the motor is increased, the power factor changes from lagging to unity and then to… Read More
2015-02-11 14:11
An electron orbiting right close to the nucleus in the 1st shell is very much firmly bound to the nucleus and keeps only a small amount of energy. Therefore initial shell has lowermost energ… Read More
2015-02-09 13:12
Introduction: A synchronous motor is a constant speed AC motor. It takes AC power by the stator from mains supply for its working in addition it utilizes a small amount of DC power which is… Read More
2015-02-08 16:53
Class “A” Insulating Material: In electrical machines of small sizes, class “A” insulating materials are normally used. Class “B” Insulating Material… Read More
2015-02-07 07:20
The various constant of the equivalent circuit of the induction motor can be determined as detailed below: Determination of Go and Bo and hence Ro and Xo: To find out Go and Bo the induction… Read More
2015-02-05 15:01
The various losses in the stator of three phase induction motor are stator copper losses and stator iron losses. The stator iron losses consist of eddy current loss and hysteresis loss. In r… Read More
2015-02-04 10:29
Stable and Unstable Region of the Slip Torque Characteristics: The torque, T of a three phase induction motor is given by &nbs&hell…Read More
2015-01-31 08:47
Construction: The slip ring induction motor could be used for industrial wires where variable speed and high starting torque are prime requirements. The stator of slip ring induction motor i… Read More
2015-01-29 04:51
In a three phase induction motor the stationary winding is connected to the three phase supply and rotor winding is short circuited. The energy from the stator winding is transferred ma… Read More
2015-01-25 10:16
The figure shows the portion of a three phase Induction motor and is principle explained below: Ø The three phase stator winding gets energized when a three phase supply is given… Read More
2015-01-22 04:43
Three phase Induction motor consist of 2 important parts namely Stator and rotor. Always the stator and rotor is separated with a small air gap ranging from 0.4-4 mm, which is depends on the… Read More
2015-01-19 11:03
The three phase induction motors are commonly used electric motors in the industry. These motor basically runs from no load to full load at constant speed. Though, the speed of the mo… Read More
2015-01-17 14:56
This test is conducted instantaneously on two similar transformers and so the transformers temperature rise, efficiency and voltage regulations. The advantage of conducting this test is very… Read More
2015-01-15 14:52
In the previous post we have seen how to determine the efficiency of DC machines using the method Swinburn's test. Now there is an another method to determine the efficiency of a DC mac… Read More
2015-01-13 06:30
In this technique, the DC Generator or DC Motor is run as a motor at no load; with that losses of the DC machines are determined. When the losses of DC machine well-known, then we can find t… Read More
2015-01-10 15:51
Introduction:To judge the performance of a DC machine either Motor or Generator there are several test conducted that are conducted. Mainly one important test named efficiency of a DC machin… Read More
2015-01-08 16:22
The figure above shows that typical representation diagram of a 3 point starter for DC shunt motors with its protective devices. It contains 3 terminals namely L, Z, & A; hence named 3 p… Read More
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