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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
The formula to use is, phase voltage /1.73 = phase to neutral (ground) voltage.
CommentThere is no such thing as a 'phase to phase', or 'phase to neutral' voltage. The correct terms are 'line to line' and 'line to neutral'. So the above answer should read: line voltage/1.73= line to neutral voltage = phase voltage.
How does on load tap changers operate?
On-load tap-changers are operated by an electric motor, often by driving a flywheel mechanism. The operation of the tap-changer is controlled by an AVR (automatic voltage regulator) which monitors the transformer's secondary voltage.
Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction, where eddy currents are generated within the metal and resistance leads to Joule heating of the metal.induction heater including high frequency induction heating machine and middle frequencey heating machine.
Induction heating applications for an induction furnace include induction welding, induction brazing, induction hardening, induction melting, quenching, forging, soldening, induction annealing and other forms of heat treatment.
Induction heating is often used to heat graphite crucibles (containing other materials) and is used extensively in the semiconductor industry for the heating of silicon and other semiconductors.
Induction heating can produce high power densities which allow short interaction times to reach the required temperature. That translates into lots of energy transferred into a material right now, with a very rapid rise in temperature.
A megger test is done to check the insulation factor of wires or devices. This is to make sure that when the working voltage is applied, a short circuit to ground will not occur due to a problem with the insulation of the device or wire.
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Is static electricity an excess of neutrons?
Static electricity is not an excess of atoms, but rather differences in the charges of those atoms. Static electricity happens when there is a separation of positive and negative charges caused by electrons moving from one material to another.
Ohm's Law
What is the resistance of 70ohms and 30 ohms in a parallel circuit?
we have this 1/Re = (1/R1)+(1/R2) for calculating the effective resistance when resistances are connected in parallel
so the answer would be Re =( 70*30) / (70+ 30)
= 21 ohms
What is the working principle of a spygmomanometer?
The sphygmomanometer is designed to monitor blood pressure by measuring the force of the blood in the heart where the pressure is greatest. This occurs during the contraction of the ventricles, when blood is pumped from the heart to the rest of the body (systolic pressure). The minimal force is also measured. This occurs during the period when the heart is relaxed between beats and pressure is lowest (diastolic pressure).
How do you convert hertz into volts?
'Hertz' is the modern name for 'cycles per second' and represents how many times an alternating current (AC) changes from + to - per second and has nothing to do with voltage that can be either AC or DC. Tus if you have an alternator and can rotate the shaft 60 times per second with a voltage of 120 volts you will produce the same AC voltage that you find in your wall outlet (Alternators produce AC while generators produce DC electricity.
What do you mean by Polarity of a transformer?
Transformer polarity is the direction the secondary goes relative to the primary, or relative to another secondary. Usually, polarity does not matter, for example in the case where the secondary is connected to a rectifier / filter / regulator. Sometimes, it does matter, particularly if there are two secondaries used to provide DC isolation between a preamp and a final amplifier in push-pull configuration. It can also matter if the overall circuit is involved in a feedback loop and phase inversion is a factor.
Answer
When applied to transformers, the term 'polarity' describes the direction in which the secondary voltage is acting relative to the direction of the primary voltage. Polarity is determined by the directions in which the primary and secondary windings are wound relative to each other.
Polarity is described as being either 'additive' or 'subtractive', and can be determined by of connecting one pair of primary and secondary terminals together. If the voltage measured between the other adjacent primary and secondary terminals is greater than the primary voltage, then the transformer has 'additive' polarity; if the voltage is less than the primary voltage, then the transformer has 'subtractive' polarity.
Knowing the polarity of individual transformers is important when two single-phase transformers are connected in parallel with each other because, if polarity is ignored, then an incorrect connection might result, causing a large circulating current through the two secondary windings.
Where would you find a forward and reverse wiring diagram?
Are you asking about a wiring diagram for the right switches to make an electric motor turn either in a forward or a reverse direction? Or for a linear motor to go either one way or the other?
If so, please ask your question again and state what typeof electric motor you are asking about, because the direction-switching circuit needed will depend on the type of motor.
Some types of motors are not reversible at all.
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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Does the current in a pure capacitive circuit lead or lag the applied voltage?
Just remember our friend ELI the ICE man!
E is voltage, I is current, L is inductance, and C is capacitance.
ELI
In an inductively reactive circuit (L), the voltage (E) comes first, then the current (I) lags behind.
ICE
In a capacitively reactive circuit (C), the current (I) leads, then the voltage (E) comes later.
Note that while your assumption (in the stated question) is correct, an engineer or electrician would not say it that way. The voltage waveform is the constant, and the current waveform is said to lead or lag. This is because reactive or non-linear loads distort the current. If you look at a power-factor meter, and it says leading or lagging, it is referring to the current. It would be more accurate to re-phrase your question: In a capacitive reactive circuit does the current lead the voltage? Yes!
Answer #2:
Another method I learned from one of my EE professor is that in an inductor the current lags the voltage because the electrons get dizzy going through all of those loops (coils) in the inductor and "lag" behind the voltage.
Overall brightness (not individual bulbs' brightness) will increase when we connect them in parallel & it will decrease when we connect them in series.
High voltage transmission and distribution lines utilise three-phase electricity. There are two commonly-used connections used in this system, termed a 'delta' and a 'star' (or 'wye') connection. A delta connection provides three energised conductors, termed 'line conductors', while a star connection provides three energised conductors ('line conductors') together with a neutral conductor. However, in the case of a star connection, provided the load is balanced, no current flows through the neutral conductor. In the case of high-voltage transmission and distribution lines, their loads are very close to being balanced, so there is no need to provide a neutral in the case of a star-connected system, as any slight imbalance can be compensated for in slightly different line currents.
Why do people say 110 volts instead of 120 volts?
Europe uses 220/240 volts, USA and Canada use 110/120 volts. The lower voltage is less dangerous if you touch a live wire.
Why primary current is higher than secondary current in transformer with turns ratio 1?
In a transformer with a turns ratio equal to 1, the primary current comprises the reflected secondary current plus the magnetizing current necessary to sustain the "back EMF developed across the mutual inductance coupling the primary winding to the secondary. Therefore the primary current is always greater than the secondary current in a transformer with a turns ratio equal to 1. This should be evident by applying Kirchhoff's Current Law to the central node of the "T-equivalent" model of a transformer.
Electrical wire splicing is the act of removing the outer shell of a wire, exposing the inside and connecting to another wire that is also spliced. This also allows you to add length to wiring.
When charging an object by conduction what happens to the charges in the object?
Electrons move onto the object, giving it a static charge.
Apex ;)
inductor was invented by scientist lenz so it is denoted by l..
Why is the function of neutral wire?
The neutral wire is simply a grounded power carrying conductor.
It is different than earth ground, which is a protective ground, that is not intended to carry current, however, earth ground and neutral are connected together at the distribution panel. Nevertheless, they serve different purposes, and may not be interchanged in usage.
The purpose in grounding one of the power carrying conductors is to limit the possible voltage potential that might exist between an ungrounded conductor, such as hot, or phase hot, so as to minimize the potential electrocution hazard that might exist if someone were to come into conduct with a hot conductor.
What is the active power consumed by pure capacitive reactance?
There is no 'active' power in a purely capacitive load. Active power is the result of the supply voltage multiplied by the in-phase component of the load current. In a purely capacitive load, the load current leads the supply voltage by 90 degrees and, so, there is no in-phase component and, hence, no active power.
In order to determine the output voltage of a transformer, you need to specify the turns ratio between primary and secondary. You did not do that, nor did you provide any other information that could be used to deduce the output, so only a general answer can be given.
The output voltage of each secondary is 10 volts (the input voltage) times the number of turns on the primary divided by the number of turns on the secondary. If, for instance, the ratio was 1:3, then the output would be 30 volts. Since there are two secondary windings, this calculation is performed independently for each secondary.
Core balance current transformer?
whats a core balance current transformer?
Core Balance CTs are special CTs used to detect Earth faults & usually used for Restricted Earth Fault Protection.
It is a ring type CT through which the cables carrying current of all the three phases (R,Y & B) are passed through. (In a 3phase 3 wire system)
Under normal operating conditions, summation of current through the three phases shall be equal to zero. In event of a fault, the summation of the current shall no longer remain zero (zero sequence current shall flow during earth fault) & thus the fault can be detected.
