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Electrical Engineering

~33500 answered questions
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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well, you either have to program the operating frequency crystal to a better remote control, (if you are using a remote control,get remote control which can control the speed) or, try using a more powerful or less powerful battery to increase or decrease the speed.
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There are several ways of doing this, but it depends on what information you have to start with.  One way is to find the impedance, using a voltmeter and an ammeter (impedance will be the product of the two readings), and the resistance using an ohmmeter (or, better still, a Wheatstone Bridge) …
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Resistance is a completely different quantity to capacitance, resistance being measured in ohms and capacitance in farads. So they are 'apples and oranges'.  You should be asking, 'What happens if capacitive reactance (in ohms) is larger than resistance?'.  And one answer would be that the…
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Safety critical systems may use circuit breakers- things like headlights.
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In a d.c. circuit, voltage drop is the product of resistance and current through that resistance.
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its cheap and easy to use.
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There are numerous ways of doing this; it depends on what information you are give to start with.  One method is:power = apparent power x cosine (phase angle)reactive power = apparent power x sine (phase angle)(where apparent power = supply voltage x load current)
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A ground fault circuit breaker essentially senses the difference currents flowing in the incomming & return wire of an electrical supply circuit.In normal cases ideally the difference must be zero or very close to it. Whenever there is a fault & the electrical path also takes any other route…
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If you interchange any two of the supply legs of a three phase motor, the motor will operate in a reversed rotation than is did before the interchanging of the supply legs.
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if it matches the current rating.... then no problem.
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A watt is a unit of power in energy per second, while a volt is a unit of potential difference, in energy per charge.  The two are not comparable.
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just the power they carry, the lines are the sameAnother AnswerD.C. transmission lines are high-voltage direct current electricity, and have less losses than a corresponding a.c. transmission lines, so are used for particularly long transmission lines. They are often used to link independent grid sy…
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Your question in ambiguous.  Are you asking what equipment you need to prove whether or not Ohm's Law applies to a particular load? If so, then you need a variable voltage supply, a voltmeter, and an ammeter.  As you gradually increase the voltage across the load, you will need to rec…
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On a normal three phase motor on the nameplate there is a value in the S.F. box. This is the service factor. Depending on the size of the motor this value will vary. Smaller size motors usually have a service factor of 1.15. See related links below.
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It depends on the power and efficiency of the motor.
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For sinusoidal voltages and currents, the root-mean-square (r.m.s.) value is 0.707 times the amplitude (peak value).
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A load current is a current drawn by an electrical load. In other words, it is the current flowing from the source to the load. For a single-phase system, a line current is a current flowing through the line, or 'hot', conductor, while the current through the neutral conductor is called the neutral…
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The syllabus for the electrical part of the ISRO exam covers things like basic technology related to electricity, circuit theory, electromagnetic fields, and the analysis of power systems.
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to achieve high voltage Wave type winding is used...... For high current Lap winding is used.
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magnitude will be sign.. Now sign will be minus...
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Most modern helicopters use jet engines.
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Steel is used to provide the aluminium conductor with tensile strength necessary for suspension between poles or towers.
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Through an omhmeter.
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You can manufacture the transformer using larger guage wire to reduce resistance.AnswerTransformers are already designed to have very high efficiencies. There would be very little you could do that the designer hasn't already done. But it would involve changing the core material (to reduce hysteresi…
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It doesn't.  It exists in all electrical machines, d.c. or a.c., motor, generator, or transformer.
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Voltage is readily available; in the US, the standard voltage of house current is 120v.  If you require a different voltage, you can alter voltage by using a transformer.
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A resistor is a poorer conductor of electricity than a metal wire ...thus it "resists" the flow of current.The higher the resistance, the lower the current ... as in I = E/R
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No.  Resistance is due to the length, cross-sectional area, and resistivity (which is affected by temperature) of a material.  It is not affected by capacitance, inductance, current, or voltage. So adding capacitors to a circuit will have no affect on its resistance.
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Front and rear.AnswerThey are located in longitudinal slots that are machined into the inner surface of the stator.
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A #3 copper conductor with an insulation factor of 90 degrees C is rated at 105 amps. A motor feeder by code has to be 125% greater than the motors full load amperage. Therefore 105 x 125% = 131 amps. A #1 copper conductor with an insulation factor of 90 degrees C is rated at 140 amps. Non-time …
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If the proper motor protection is in place, the motor's contactor will drop out and take the motor off line. If no motor protection is in place the motor will single phase. This will put a higher than normal operating current on the other two legs of the motor's windings.AnswerIf you actually mean '…
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DC flows steadily without changing, while AC is continuously reversing its polarity. A good approximation of the voltage waveform of an AC suppy is V = Vp sin (2.pi.f.t) and it is commonly called a 'sine-wave'. In the equation Vp is the peak voltage and f is the frequency. In each period of 1/f th…
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Alternating current usually has a frequency of 60 cycles per second.  This is not determined by a formula, it is determined by the rotations per second of the turbine which generates the current.
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i think both will be same..
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number of turns......... If turns is more than more impedance..
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it will improve the power factor... The angle between voltage and current will decrease depends on capacitor value.
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For a step-down transformer, its secondary winding will be the LV winding. For a step-up transformer, its primary winding will be its LV winding.
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Pakistan has a 220 v 50 Hz domestic supply and the three-phase voltage is sqrt(3) times higher, or 381 v. Higher voltage are also used for three-phase power transmission.
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The lamps will vary in brightness, with the brightest being those having the lowest rated power, but all of them will be dim compared with their normal brightess.
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The current in a passive DC parallel circuit divides in inverse proportion to the resistance of the branch, as I recall. So, since the 10-ohm is 2/3 the resistance of the 15-ohm, it ought to carry 3/2 as much current. We can call the current through the 10-ohm "3/2" and the current through the 15-oh…
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Approximately the same as the voltage between line and neutral.
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First ac has to be rectified into dc and then that could be stored in a secondary cell in the form of chemical energy.
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in order to avoid unwanted short circuit break downs.... short circuit can burn the transformer and motor winding.... Megger is the device used to check the insulation .
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By using a three-phase alternator, whose armature windings are physically displaced from each other by 120 degrees.
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Power is voltage times current times power factor. The power factor is determined by the load. As the transformer manufacturer has no idea of the power factor of the load the transformer is to supply, he can only specify the transformer's rated current and rated voltage, the product of which is appa…
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There are two conditions that would cause a breaker to trip off. One is an overload of the circuit and the other is a short circuit on the circuit. The heating element within the breaker is what monitors for circuit overloads.
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The ratio of apparent power to true power is called 'admittance', expressed in siemens. Admittance is the inverse of impedance.
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It depends on the nature of the circuit.  In a purely-resistive circuit, the current would rise immediately because resistance merely limits its value, it doesn't oppose any change in current. But in a resistive-inductive circuit, for example, the inductive component opposes any change in curre…
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In Surface Grinding, the kind of motor that is used is an A.C. Motor i.e the motor that operates with Alternating Current. The current amperage and H.P. specifications depends on the type of Grinding wheel as well as the type of work piece to be used to be ground.
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A three phase 30 HP at 240 volts draws 80 amps. Motor feeders have to be rated at 125% of the motors full load amps. 80 x 125% = 100 amps. A #3 copper conductor with an insulation factor of 75 or 90 degrees C are rated at 100 and 105 amps respectively.Non-time delay fusing is 225 amps, time delay f…
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it is not possible.......
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There is 1 ohm in 1 volt.
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Ohms are used to measure resistance, and volts are used to measure potential difference  -two completely-different quantities. You might as well be asking, "How many kilometres are there in 12 degrees Celsius?"
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To supply required reactive power.... also to improve the power factor of the line..
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in order to reduce the transmission line losses we need low impedance...Low impedance also improves power transfer capacity of the line..
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Actually the opposite is true. The heart is far less likely to be hit by DC and the body usually jumps BACK from the DC source. Also many tests have been done including actual execution(s) in which DC was used. It had taken much longer for the subject to die and the scene was horrible beyond repriev…
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to reduce current and the resulting I2R waste of power.
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You cannot measure DC current with a transformer.  You can only measure AC current with a transformer.Another AnswerPower grids are generally a.c. systems, with d.c. being reserved for either very long-distance transmission lines, undersea cables, or as links between independent a.c. grids. &nb…
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In very simple terms, you divide the load's power by the supply voltage, in order to determine the load current. But, in practice, it is much more complicated that this because you may need to take, for example, diversity into account. 'Diversity' tells us, for example, what percentage of a range's …
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XLPE cable has high electric strength,mechanical strength,high-agcing resisting,environmental stress resisting anti-chemical corrossion,and it is simple construction,using convenient and higher operating of long term temperature.It can be laid with no drop restriction. Various of flame-retandant a…
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i can fit da 180v dc motor . i wil put 1 inverter n selfrunning12v genrater to charge da inverter batery continosly.
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Diode is known as a rectifier because it only allows the current to flow in one direction. Diode is only effective when the input is AC.
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No.  You can not step up power with a transformer.  You can step up voltage, while stepping down current, or you can step up current, while stepping down voltage, but you cannot step up (or down) power.
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The term is 'fractional', not 'frictional'!  A 'fractional kilowatt' motor is simply one with a rating below one kilowatt.  In North America, the equivalent term is 'fractional horsepower', meaning 'less than one horsepower'.
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In new installations, when installing three phase motors, it is a 50 - 50 chance that the motor will turn the correct rotation. There is an instrument that can reduce these odds to 100% correct each time. The three leads are connected to the three motor connections. The motor is hand rotated in the …
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A single-phase supply is obtained between any two line conductors or between a line and neutral conductor of a three-phase supply.  To obtain a three-phase supply from a single-phase source is far more difficult, and requires additional equipment.
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in dc circiuts only resistors are responsible for voltage drop. where as in ac circuits inductances and capacitances are also responsible for voltage drop in addition to that of ressistors
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it makes sound :) trollolololol
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For radios 6 volts, for cars 12 volts, for large vehicles 24 volts, for submarines 220/440 volts.
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yeah of-course..... for DC circuit holds good...:)Another AnswerYou can use the ratio of voltage to current to determine the resistance of a conductor or other device for that particular ratio. But you must remember that Ohm's Law is not a universal law, and only applies to linear or ohmic devices.
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no..... The battery with lower voltage will consume power from the higher one...
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If you use synchronous generator... you need rotor to rotate always in synchronous speed... practically it s not possible always to produce that speed by air flow... Air flow always varies...But using induction generator, you need to get speed to make slip as positive value.. it is always possible..…
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Only one service is allowed to a single family dwelling. An open delta or high leg delta is a commercial or industrial service and these days are rarely used as the utility company's are trying to standardize their equipment. Three phase supplied services come in either a wye or delta configuration.…
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'Salient' means to 'stick out', so salient poles stick out from the machine's shaft, as opposed to shafts which are slotted to contain its windings.
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1000 microfarads is its rated capacitance, while 35 volts is its rated voltage.
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It can and it can't.It's advantage is the lack of rolling friction (no wheels)but air resistance still applies.When "high speed trains" went 100 mph then mag-lev looked real speedy,but with High-speed rain now pushing 250 mph, mag-lev is only slightly faster.(And don't forget, mag-lev uses a lot mor…
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If more than one winding is burnt open the motor will not operate.
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The higher wattage motor would be the 120 volt at 12 amps which equals 1440 watts. Another AnswerTo answer your question, it's necessary to compare 'like with like'. And the information you supply doesn't enable us to do this because, for the 230-V motor, you are specifying its output power wherea…
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There is no problem as such.  Whether you would want to, or need to, is another matter.
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To answer your question properly, you need to know the input power to these machines, whereas you are specifying their output powers. In other words, you really need to know their efficiencies in order to determine their input powers.Once you have figured out their input powers, then you need to div…
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'Torque' applies to any motor, not just to a.c. motors.  It is a turning moment, defined as distance multiplied by the force acting at right-angles to the shaft.
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It 'travels', via the transmission and distribution systems, to the load (i.e. factories,  residences, etc.).
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It can carry 20 amps in most situations where the wire is uncoiled and normally ventilated.
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Current will cease to flow in a series electrical circuit.
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Current doesn't 'pass through' a transformer.  There are two currents: a load (or secondary) current and a primary current. To measure these you would have to use two ammeters:  one in the primary circuit and the other in the secondary circuit.  If we are dealing with high voltages, t…
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All electricity is generated, transmitted, and distributed as three-phase.  Three-phase a.c. is generated by an alternator with, essentially, three armature coils that are physically displaced from each other by 120 degrees. Thus each of the three wires leaving that generator reaches its peak p…
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Used in this way, the transformer will tend to overheat.  But it is quite okay to operate a 50-Hz transformer at 60 Hz.
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Yes.  For a condition called 'series resonance', if the resistance of the circuit is low compared with the inductive reactance and capacitive reactance, then the voltage drop across the capacitor can be VERY much higher than the supply voltage.
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Yes this could be true. The breaker to the load will have tripped. The main breaker should still be allowing voltage to the distribution panel because it did not trip. If the main breaker tripped then the distribution panel must have been close to maximum amperage and the shorting of the branch ci…
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Answer for European SystemsThe nominal line-to-line voltage used for single-phase supplies in Europe is 400 V.  In the UK, this voltage is allowed to vary between -6% and +10%;  in other words, it can vary between 376 V and 440 V. So it would be quite acceptable for a 380-V and a 415-V mot…
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Vector groups are used to categorize high and low voltage in transformers. The group number identifies the phase angle between configurations.
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Through the use of the basic transformer voltage equation.
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The frequency is dependant upon what electrical grid that you are connecting the transformer to. If you are connected to a 50 Hz grid, the transformer will output a voltage at 50 Hz. The same thing with the 60 Hz grid, the transformer will output a voltage at 60 Hz.
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Every component in a series circuit must have a potential difference across its terminals if current is to flow through that component.  We call each of these individual potential differences a 'voltage drop', which is actually a bit of a misnomer as it's not really a 'drop' at all; it would be…
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