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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

What is vector group of power transformer?

Hi first of all Vector group used to determine the PHASE shift of the TRANSFORMER as well as the PRIMARY and SECONDARY connection information.

Let taken an example:-

YNyn0d1 It means CAPITAL LETTERS indicates the primary side of winding detail's small letters for secondary side detail's DELTA CONNECTION Symbol D OR d is used and connection WYE used Y OR y for PRIMARY and SECONDARY.

If WYE connection is their neutral always come so we used suffix N OR n.

Now check PHASE angle Difference (PHASE ANGLE) see the last NUMERIC VALUE give correct information.

Suppose we connect/compare two TRANSFORMER we first see its VECTOR GROUP if they matched then we do move to any connection.

If any quarries fill-free to ask

ajay.sahu099@gmail.com

What is voltage ratio on a transformer?

The voltage ratio of a potential, or voltage, transformer (PT or VT) depends upon the primary voltage to which it is connected. Accordingly, its voltage ratio varies considerably, as there is huge variety of system voltages throughout the world.

Typically a VT's secondary voltage is standardised at 110 V which will match the full-scale deflection of a voltmeter connected to it (although it can also supply protective relays), while its primary voltage is then matched to the voltage of the system to which it is connected: in the UK, for example:

  • 11-kV:110 V
  • 33-kV:110 V
  • etc.

What is over load relay?

to be protect the motor and electrical equipments.some circuit provide to protect the motor.for exm.DOL starter, OLR to protect the motors....

What is the function of brush in a dc generator?

It has two main functions in a generator - firstly, it transfers the electrical energy from the (moving) armature coils to the (stationary) external electrical load circuit. The brushes are made of graphite, with a tiny trace of copper in it, so they're self-lubricating where they ruib on the copper commutator bars (those copper strips on the armature that the coil ends connect to).

Secondly, the electricity generated in the rotating armature coils is alternating current, and the brushes, working with the commutator acts like a switch to reverse the connections between the coil ends and the external circuit when the alternating voltage reverses its polarity (+ and -) to give direct current in the external circuit.

Have a look at http://community.myelectrical.com/wikis/myelectricalwiki/basic-generator-operation.aspx for more information.

What are advantages of transducer?

What is piezoelectric effect. Every day use of this phenomena is used in load cells. Load cells are used on large weigh scales for trucks and large bin scales where materials need to be weighed. The signals from the cells are calibrated to compensate for the weight of the scale so that the scale can be zeroed out. The cell signal, because it is very small, is sent to an amplifier head where is can be read by the operator in units of weight. The head unit can be set to read in metric or imperial weights. Advantages. As explained in your above question on weigh scales the load cells do away with all the mechanical linkages that the old systems had to use. These linkages were always prone to mechanical damage where as the load cells are self contained sealed units. There are four units per scale, one under each corner. I brought my two answers together to make more sense

Truth table for 3 input xor gate?

Exclusive Or means "one and only one of many", so the truth table of a 3 input XOR gate would be

000 0

001 1

010 1

011 0

100 1

101 0

110 0

111 0 ... or 111 1 ... see note

Many references say that 3 input XOR gate's output should be 1 when the no of 1s in inputs is Odd, and 0 otherwise. So in the given truth table, when the input is 111 output must be 1 , i.e. 111 1

plz note -- for 111 1 must be the optput.. i confirmed it

How are printed circuit boards manufactured?

Printed circuit board are electronic circuits created by mounting electronic components on anonconductive board, and creating conductive connections between them. The creation ofcircuit patterns is accomplished using both additive and subtractive methods. The conductivecircuit is generally copper, although aluminum, nickel, chrome, and other metals are sometimesused. There are three basic varieties of printed circuit boards: single-sided, double-sided, andmulti-layered. The spatial and density requirement, and the circuitry complexity determine thetype of board produced. Printed circuit boards are employed in the manufacturing of businessmachines and computers, as well as communication, control, and home entertainment equip-ment.

What is the main purpose of a transformer?

step up transformer output gives the high voltage which is useful for transmiission of electricity

How is total resistance in a series circuit determined?

Series circuit: The total voltage is the sum of the voltage on each component. The total resistance is equal to the sum of the resistance on each component. The total current is equal in every component.

How many amps should a 0.5 horsepower motor draw?

Depends on the voltage. If you are running off 120 VAC, a 0.5 horsepower motor would draw 3.1 A.

What do you do before working on electrical equipment?

If I were asked to check a piece of equipment already installed with no other information, this is what I'd check:

1. Check the voltage and amp requirements of the equipment

2. Verify it is fed from a panel and breaker of the proper voltage and amperage

3. Verify wireways are properly installed

4. Verify that proper size wire is used and that the equipment is properly grounded

5. Verify terminations are made properly

6. You may want to verify with a meter that proper voltage is being supplied. In most cases you can trust the labeling on the panel but it never hurts to check.

In all these verifications you are checking for workmanship, not just technically accurate installation. If something doesn't look right, check it out closely and look for other "red flags" that might signal someone didn't know what they were doing.

For single phase equipment and three phase equipment without a motor you are ready to turn it on. NEVER look at a breaker or equipment terminals when energizing. You only have one set of eyes.

For three phase motors you need to check rotation. This is done by "bumping" the motor by turning it on only for a moment. If it rotates correctly you are good to go. If it doesn't, switch any two leads either at the equipment or at the breaker and bump again. It should rotate in the right direction and should be ready to go.

If capacitors block the ac signals then why they are used in dc circuits?

Capacitors don't 'block' a.c. signals; they block d.c. signals. But there are lots of different reasons for using capacitors apart from their ability to block d.c. signals.

Explain the formation of depletion layer in pn junction diode?

hey dear, in p-n junction p-type material has more positive charged called holes and n-side having e-in majority... when we apply negative biasing then negative terminal is connected to p terminal then holes are attracted by negative terminal and e's are attracted by positive terminals.....and minority carries are forced towards junction, then at junction electron and hole pair generation occurs. after this at junction charge is accumulated by attraction and junction is get wider by a small amount that is called as depletion layer...... now you can understand how depletion layer is created..

Why an inductor filter cannot be used in half wave rectifier?

I am not exactly sure why it is said it can't be used, I myslef was searching for an answer when I came across this, I have a general idea about this, why I would like to share.

There can be two possible reasons.

1. The inductor produces a back-emf which opposes any change in current, but in the output of a HWR, the decrease in current and a no current state predominates a increase in current, so the inductor will naturally oppose a increase in current, which will mean a low dc voltage is obtained. [i.e. lower than the peak value]

2. The reactance of inductor increases with increase in frequency, the output frequency of a HWR is half that of a FWR. Thus filtering of higher harmonic waves is favoured.

Please check this out as well. http://books.google.co.in/books?id=FEdLZZgCe6YC&pg=PA85&dq=%22inductor+filter%22+HWR+OR+Half-Wave-Rectifier&lr=&as_brr=3&ei=NlgkSZ3VApHakASXq92BBQ#PPA84,M2

Aghosh Babu Plamkandathil

aghoshx(at)gmail.com

What does a solenoid do on a valve?

A solenoid valve is a type of valve that uses an electrical current to actuate or shift a spool or cartridge consisting of a solenoid coil and tube assembly.

Basically, this valve type uses an electric current to shift a pin to perform simple A/B tasks such as open/close valve spools.

The designation "solenoid" means that the valve operation is electrical not manual.

Maybe the easiest way to describe a solenoid valve is by thinking about an automatic car lock. The electric current get triggered, the pin gets pushed up and the doors are unlocked. A reverse current gets triggered, the pin gets pushed down, and the doors are locked.

What is the reason for ferranti effect?

Ferranti Effect causes the receiving end voltage to be more than the sending end voltage. It occurs mainly in long transmission lines when they are lightly loaded. In this condition, the inductance of the lines becomes more resulting in increased receiving end voltage.

What will happen to the output ac signal if the dc level is insufficient?

What will happen to the output ac signal if the dc level is insufficient? Sketch the effect on

the waveform.

What is the latest ICT hardware?

ICT Printing Press is product for offset Printing Press. It simply takes few related parameters of customer's order as input and present total estimation of project, most economical job size, machine, paper stock cutting plan for sheet or reel. It is newest ICT HARDWARE.

What is the distance of 132 kV tower?

It varies, according to their height, and the landscape (i.e. the levels of the ground) between towers, as well as upon any restrictions on where towers may be built. The determining factor is to ensure that the ground clearance of the conductors remain above their regulation clearance.

How do I determine RPM of a 3v DC motor?

RPM stands for revolutions per minute. This is calculated for different devices and can indicate how fast something is going. For a DC motor, the RPM is calculated by how many times the motor turns.