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Electrical Engineering

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Parent Category: Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.

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Institution of Electrical Engineers ended in 2006.
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P = I x E (where E is voltage) so it's linear. ==== The power dissipated by a component or circuit depends not only on the voltage across the load, but also on the characteristics of the load itself. If the resistance/impedance of the load is constant, then P = E2/R so it's proportional to t…
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Mutual induction between 2 or more coils.
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•The RMS line voltages of the two generators must be equal. • •The two generators must have the same phase sequence. • •The phase angles of the two a phases must be equal. • •The frequency of the new generators, called the oncoming generator, must be slightly higher than the fre…
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The basic parts of a transformer are the core and the windings. However practical transformers often have many more parts: the core could be solid or composed of possibly hundreds of laminations the windings could be wound directly on the core or on one or more bobbins a shield may surround the …
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Suspension insulators are glass 'dish' insulators that are designed to take longitudinal strain -i.e. strain in the direction of the conductors. They are so-called, because they are suspended below the pole's crossarm. Suspension insulators, therefore, are used on terminal poles where the main strai…
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Yes, Kirchhoff law is applicable to linear circuits. In fact, both of Kirchhoff's laws are applicable to ALL circuits, because they're just conservation laws.
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For protection.. Since the current prefer the short cut ..
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The difference between current transformer and potential transformer is that the secondary of a current transformer can not be open circuited while under service whereas that of the potential transformer an be open circuited without any damage to the transformer.
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Depends on the load. It'll probably turn, but slower and weaker than on 12V.
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------- I have moved what you have written to the discussion page, where we can carry on with more details if you need them. ------- First of all the US does not have 2 phase power systems. What North America uses is a split phase secondary that is used to power home. In a single phase service, t…
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In a series circuit all elements connected to it have the same current, with symbol I, also called intensity, measured in Amperes. On the contrary, each element has a different voltage unless there are two of the same elements. For example. You have a 10 Volts battery, connected to 3 resistances: 1…
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In basic the load is commonly referred to in relation to the outputs required by that circuit. i.e. How many x wattage lamps will, as a maximum be on a circuit. therefore the term 'load' may refer to the power consumed by a circuit
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Normally use of number, communication skills in the language that they will work in, ability to work in a group or on their own, ability to identify what needs to be learned to maintain their legal levels of competence and to improve throughout their learning stages, ability to read and create drawi…
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Rectifiers turn A/C into D/C, but transformers can only run on A/C.
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Watts are volts multiplied by current while volts are the electrical potential difference.
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The IEEE (Institute of Electrical and Electronics Engineers) was formed in 1963 by the merger of the Institute of Radio Engineers (IRE, founded 1912) and the American Institute of Electrical Engineers (AIEE, founded 1884).
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The answer to this homework question is that 2 amps represents a flow of 2 coulombs of electric charge every second.
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A step up transformer increases the voltage and decreases the current, however a step down transformer will decrease the voltage and increase the current
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The power consumed is: Power consumed or power of the device, its about 1 KW multiplied by Number of hours or minutes or seconds, ALWAYS expressed in HOURS So, a microwave with a characteristical power of 1 KW used for 1 hours would use a KW-hour shortened with KWh if used half an hour it would…
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A fixed capacitor can be used for power-factor correction for a single-phase ac appliance such as an induction. One of these can also be used to suppy a phase-altered current to the starting winding on the motor. In electronics fixed capacitors are used in shunt for decoupling, which earths any ac…
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A trimmer capacitor is a semi-adjustable capacitor placed across a variable tuning capacitor and pre-set to allow the main capacitor to track correctly with another variable capacitor on the same shaft. The adjustment takes out any differences introduced by the connected circuit.
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If the slab is zero thickness, nothing. The lines of electric field not intercepted by the slab are unaffected, so what goes on there is unaffected. The part where the lines are intercepted is converted to two capacitors in series, and the charges on opposite sides of the slab are equal and opposite…
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I suppose that this value is 1 picovolt (10-12 volt). The symbol is pV.
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The Line normally refers to the live wire in a single-phase system and the three live wire of a 3-phase system. In a 3-phase system the line voltage is usually quoted as the nominal voltage, and that is the voltage between any two of the live wires. The voltage between one of the lines and neutral…
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Oil or similar is used as a cooling fluid in electrical transformer, because it is electrically insulating - which water is not. The figure of merit is the lack of conductivity.
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Because they are all hooked up is series, like links on a chain. Break one, and there's no current coming through to the next one
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Losses are undesirable in any kind of electric motor (DC, AC, stepper, servo, synchro, etc.) because they waste power, can cause excessive heating in the motor, can accelerate wear-out and cause premature failure of the motor, etc. Ultimately they are undesirable because the problems above increase …
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The Star-Delta control circuit diagram shows the delta contact and the main contact.
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Yes is the short answer. Most Christmas tree lights are wired series - parallel so this doesn't happen.
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The thermistor motor protection relays CM-MSE, CM-MSS and CM-MSN are used to control motors equipped with PTC temperature sensors. The PTC temperature sensors are incorporated in the motor windings to measure the motor heating. This enables direct control and evaluation of various operating conditio…
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The correct term is the conductivity of the metal. The conductivity of different metals can be found tables on the internet. Examples are: Silver (best) 6.30 x 10 to the power 7 S/m Copper 5.96 Gold 4.10 Aluminium 3.50 Tungsten 1.79 Copper is the most widely used metal for electric current…
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That will depend on the function of the linear circuit and the spectrum of the AC source. Without knowing both of those things there is no way to answer this, and you haven't specified either one.
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Most people would agree that hv transformers, if that means transformers for over 1000 v, are never small. The size of a transformer is determined by physical limits. The iron-based magnetic core of a transformer is a material with a limit to the permitted flux-density allowed if losses are to be …
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Always. Any current that flows, goes out on the live line and returns (completes its circuit) on the neutral line, and in the other half of the cycle the flow is reversed. The description "neutral" is given to the wire which has near to zero voltage with respect to "earth", while the other power lin…
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I guess you could use a thermal delay relay... or about 1000 other ways depending on the exact requirements.
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generators are machines that convert machanical energy to electrical energy and could be AC or DC. if in a DC generator has it field armature connection in both series and parallel its said to be compound dc generator.
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Yes. The blower motor of an air handler unit can be considered as an ignition source.
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Yes. The blower motor of an air handling unit can be considered as an ignition source.
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A megohm test in which the resistance of the insulation is measured in relation to ground. Any reading over 1 megohm is good to use on a low voltage potential.
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AF means audio frequency. Audio Amplifiers can be subgrouped as voltage amplifiers (or pre-amplifiers) and power amplifiers. The voltage amplifier will raise the level of level of the output of a microphone from say 1 mV to 500mV or 1V. The power amplifier will be the interface between this and the …
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In U. S. household wiring the two primary phases of 110 to 120 volts rms are 180° out of phase with each other which is why the voltage measured from line 1 to line 2 is double that of each line measured to the common return. The outputs of two identical transformers would therefore be additive if …
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Transformers don't work on DC. If the voltage supplied isn't the one you want, it can be difficult. If you want a negative earth, and someone else in the house wants a positive earth, you have problems. Transmission of DC over large distances has problems (to get low currents to ensure low transmiss…
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We are not told what the theoretical value is, nor what the experimental results are, nor what the significance of the mention of equivalent resistance is, so nobody can satisfactorily answer this question.
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It may or may not be so. If one resistor of the arrangement completely fails, then in a series circuit the resistance becomes infinite. In a parallel circuit the resistance will rise to the value determined by the remaining resistors. Which of those results is better or worse depends on the applicat…
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Standard cell characterization is determining electrical properties of a circuit (timing, power, noise, capacitance etc) using simulation. See www.paripath.com, a provider of Standard cell characterization software, for more information.
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You need to find out if it's a DC or an AC motor. If it's DC you need to know if it's series, shunt or compound. If it's AC you have to know if it's a commutator motor, an induction motor or a synchronous motor. To calculate the performance, that depends what point you are starting from, in other …
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Operational amplifiers are used in many applications where a well defined transfer function is needed. In former times they were widely used in analogue computers and simulators. The ideal op-amp is a phase-inverting voltage amplifier with infinite input impedance, zero output impedance and a very…
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Yes its called an inverter.
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It is carried out by tap-changing on the HV side of the transformer. The number of turns on the winding is increased or decreased by a number of turns to make the secoondary voltage take the right value. Tap-changing is done on the HV side because each turn is a smaller percentage of the voltage, …
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A simple single-phase installation for an average European house has a supply provided on two wires, the live and the neutral, with a nominal voltage of 230 v. Single phase supplies are usually rated at 60 or 100 amps. In countries which use 120 v appliances the property is usually supplied with a…
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There are literally thousands of different MOSFETs that are suitable for such an application, each with different ratings. Thus there is no single answer possible here.
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European transformers can be sold in China provided they have the relevant CIQ from the Chinese authorities.
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Power supply providing constant D.C. output voltages from variable A.C. input voltagesThe novel power supply for generating a constant d.c. voltage from a variable a.c. voltage supply line, includes a plurality of switch circuits (10, 12) which monitor voltage levels on respective secondary windings…
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U use a beromeater
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The same as what? when an inductor is connected in series with a resistor and a current passed through them, the voltages across the resistor and inductor are equal when the reactance is equal to the resistance: 2.pi.f.L = R
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It cranks the engine over in order for it to start running.
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If it can be adapted to fit, it is a little more powerful
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Put the key in the alarm disable lock and turn. There are two types of door systems. One as above, which is a free standing door system and the other where the door is tied into the buildings alarm system. In both cases the person that looks after the buildings security has to be notified. They wil…
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Kinda-sorta. It won't break, but it won't get particularly warm either.
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You may not know this, but Ohm first did the experiment incorrectly and came up with a wrong and very complicated equation for what is now called Ohm's Law. He even published a paper giving this wrong equation. It was only after the journal in which his incorrect paper was published had been out f…
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Because those metals have a high meling point, so it's easier and safer to use fuse wire which melts at a lower teamp.
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Commonly relates to devices or equipment which are designed to do some task involving delivery of power, electrical or mechanical. The receiver or this power is called the "load" (for example, a light bulb, or a public lift activated by a motor). If such a load is disconnected (electrically or mecha…
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The power lost by hysteresis depends on the peak flux density in the core. If the transformer is getting hot even when on no load, it should be run at a lower voltage.
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An induction motor connected to an existing ac supply normally runs at less than the synchronous speed by an amount described as the 'slip' which is proportional to the torque demanded at the shaft. If the same motor is instead coupled to an engine and driven at a speed higher than the synchronous…
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Single phase is not preferred over three phase, it is the system used that the application needs to operate with. There are more single phase installations than three phase due to the fact homes operate on that system. Where as most commercial and industrial applications call for a three phase syste…
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Wattmeters are not used for loads which are purely capacitive or inductive, because no watts are consumed and no energy is consumed by the customer. But amps must still be supplied by the power company to supply the customer's capacitive or inductive load and the result is measured in volt-amps re…
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It depends on the line, but AC high tension lines are typically between 100kV to 750kV while some DC high tension lines are as high a 1MV.
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maximum current of a 1hp
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A 6 kVA generator could supply a 6 HP compressor motor.
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Using three-phase or singe-phase motors depends mainly on what type of electric power supply is available. Most small properties have a single-phase supply of up to about 24 kW (100 amps). Properties requiring more power can be supplied with a second phase from a three-phase neighborhood supply, o…
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A very very tiny amount of the current that would normally flow through the resistor instead flows through the voltmeter, allowing it to make its measurement. For most purposes this very very tiny amount of current can be completely ignored.
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They are important because they are used to plug in to the electricity supply. The three pins are live, neutral and earth, also called hot, neutral and ground.
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Cross section is the surfave area of the cable if you imagine it cut into ... gauge and diameter are basically the same thing, although the unit of measurement are different.
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Fixed-value resistors are normally manufactured so that they obey Ohm's Law -that is, the ratio of their voltage to current remains constant for variations in voltage, within specified limits. In other words, their resistance value remains constant for variations in voltage. This would produce a str…
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Actually that diode is made by is made by joining a P type semiconductor and an n type semiconductor together.
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Copper carbon decides the distribution of commutation from the rotation. It tells what direction for it flow.
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The voltage cannot just be increased in a circuit because there is a risk of damage, blown circuit breakers and/or fire. However an appliance desgined to run on 220 v will use 6/11ths of the current used by an identical appliance designed for 120 v.
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It depends on the type of motor, its size and whether it's AC or DC. For a DC motor it depends on the armature resistance, and the field winding resistance for a series motor. A resistor may be added to limit the starting current. For AC it depends mainly on the inductance of the field winding.
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No, it needs several other components and a source of power.
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It turns it into light, and some heat.
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The tunnel diode is a two terminal device that is capable of being used as a small signal amplifier when properly biased.
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In three-phase systems, a fault may involve one or more phases and ground. This functionality is not as common on underground systems as faults.
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Because the motor is much simpler and easier to design when the electrical power is supplied to the stator, while the rotor is a short-circuited copper cage. It allows the motor to work with no commutator or slip rings, so induction motors are quiet and have a very long life.
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The load on a motor can be measured in watts, and it is the mechanical torque supplied, multiplied by the speed of the shaft. When the torque is in Newton-metres and the speed is in radians/second, the mechanical power output result is in watts.
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The sag setting is necessary because it is physically impossible to have a suspended line with no sag. The sag is specified because there has to be a minimum clearance value for the height above ground at the centre of the sag where the cable is at its minimum height.
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It's just the way three-phase works. The three live lines have a voltage of 230 v to neutral, let's say, and then the voltage between lines is 230 x sqrt(3). It happens because of the way the three voltages are timed, or phased, to peak in turn regularly through the AC cycle.
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A polarised capacitor is one that can only have a voltage applied to it with the right polarity. Electroytic capacitors provide a large capacitance in a small volume but they are polarised and have a positive terminal and a negative one. They are damaged if the voltage is applied wrongly.
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Because it has to be 1 when the phase angle is zero.
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It does not depend on the line. The regulation is the percentage change in voltage caused by applying the full load current, and that depends on the transformer supplying the line. A value of 5% would be typical.
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For a single-phase induction motor, allow 7 amps on a 240 v for a 1-HP motor. Therefore the formula is: current = 7 X HP x 240 / voltage
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The performance curve can be a graph of torque versus speed. The torque is zero at zero speed and also at the synchronous speed. Normally an induction motor operates at 90-97% of the synchronous speed, where the slip is between 10% and 3%. In this region the torque is proportional to the slip. As …
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A DC machine works by passing a conductor (on the armature) through a magnetic field provided by the field winding. The voltage produced by the armature is proportional to the field strength and the rotation speed of the armature.
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Because a battery works by the chemical action of the electrolyte on the plates. The process works slowly, and it works with a constant potential, which is inherently DC.
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