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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
Whats the difference between a switch fuse and a fused switch?
A fuse's main purpose is to quickly disconnect a short circuit from the distribution system. A circuit breaker has a twofold function: it trips on a short circuit by utilizing a magnetic sensor device and it also trips on a thermal device which senses a current overload that is higher than its rated current. Both devices are housed inside the breaker case.
Fuse: When the current passing through a fuse exceeds its rated value it physically burns through a thin strip of metal and opens the circuit so current can no longer flow. You have to get a new fuse to restore operation.
Circuit breaker: When a circuit breaker trips it opens a mechanical switch to interrupt the flow of current. You just need to reset the breaker and you are ready to go again.
In both cases you must always be sure to remove the cause of the over-current situation because, if you don't do that, the effects of a blown fuse or a tripped breaker will continue!
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Fuses and circuit breakers were invented to protect electrical items from being damaged by taking too much current (amps), something which is also known as an over-current fault condition.
FusesHow a fuse worksWhen an over-current fault condition occurs, which is the same as saying the current gets bigger than the fuse can carry, its internal "fuse wire" gets so hot that it melts and breaks apart, which cuts off the supply of current. When that happens the fuse is said to have "blown".
After whatever caused the over-current fault condition in the circuit has been repaired, a blown fuse must either be replaced with a new one or, if it is the type of fuse which can be rewired, it must be repaired using the correct size of special "fuse wire".
A new fuse should then remain in place un-blown until another over-current fault condition occurs in the circuit it is protecting, which would then cause the new fuse to blow.
What are the advantages and disadvantages of fuses?
To give the same over-current protection, fuses are generally cheaper to make and smaller in size than circuit breakers.
However an ordinary fuse cannot blow as quickly as a circuit breaker can "trip".
Some equipment may require special "quick-blow" fuses so that damage can be prevented when an over-current fault condition occurs. Quick-blow fuses cost much more to make than ordinary fuses but must sometimes be used where a circuit breaker would be too expensive and/or too large in size.
Further notes about fuses:
- Some fuses are rewireable, meaning they can be repaired if they blow. This must only be done using new fuse wire of the correct size. It is dangerous to use fuse wire which is thicker than the size marked on the rewireable fuse's body.
- Other fuses, known as "one-time" or "cartridge" fuses, cannot be repaired when they blow. If that happens they must be thrown away and replaced by a new fuse of the correct size.
Some one-time fuses look like small cylinders with a metal cap at each end; others look like a small cylinder with a metal screw-cap on one end like a light bulb. One-time fuses for vehicles, known as "fuse-links", have small bodies made of plastic and two metal blades which push into fuse slots in the vehicle's fuse box.
If a one-time fuse blows it should only be replaced by a new one of the correct size (Amps) for the circuit. The ones which screw in have different sized screw-caps for each size of fuse, with matching sockets to ensure that only a fuse which is the correct size can be screwed into the fuse holder. Similarly, fuse-links have different sized metal blades and matching slots to ensure that a given slot can only accept the correct size of fuse link.
When an over-current fault condition occurs, which is the same as saying the current gets bigger than the circuit breaker was designed to carry, it's mechanism causes its switch contacts to open, which cuts off the supply of current. When that happens the circuit breaker is said to "trip".
When whatever fault condition in the protected circuit has been repaired, the circuit breaker can be "Reset" by pressing a button to close its switch contacts. The contacts should then remain closed until another over-current fault condition occurs in the circuit it is protecting, which would cause the breaker to trip again.
What are the advantages and disadvantages of circuit breakers?
To give the same over-current protection, circuit breakers can be designed to trip much faster than an ordinary fuse but they are generally larger in size and cost more to make.
However circuit breakers are re-usable and can easily be reset after they have tripped - provided, of course, that the fault condition in the protected circuit has been repaired.
A fuse is a protective device that destructively opens when the current flow exceeds a preset value. It is usually designed as a low value resistor that heats up and melts at the specified current value. Once the fuse blows, it must be replaced.
A circuit breaker is a protective device than non-destructively opens when the current flow exceeds a preset value. It is usually designed as a tripping relay/switch that can be reset and reclosed when the fault is cleared.
In both cases, the design can provide for different preset values as a function of time. It depends on whether the intended load pulls a larger startup current than when it runs, such as a motor, which can easily pull four times their run current when they startup. The protective device is selected for the specific type of load, and for the rating of the conductors supplying it.
What is the function of timer in an electric circuit?
Answer
A timer is used to time things. For example if you think of how many truck there are rolling down our highways it would be amazing, but they are on a timer of sorts. They have to deliever on time or they get penilized for being late. Timers are used on inside and outside lights, there are tons of uses for timers.
How to change polarity of current?
You might be asking the wrong question. In North America, utilities deliver 120 volts AC at 60 hertz. This means the voltage at your electrical outlet rises to positive 60 volts and then goes to negative 60 volts. The 60 hertz means this happens 60 times a second.
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If you mean you have an outlet with hot and ground or hot and neutral reversed, you should call an electrician. You can buy a cheap tester that will plug in to show you if you have a receptacle mis-wired this way. If the receptacle has a black and white wire connected, and the black wire is not the "hot" wire, it can be tricky to trace down the problem.
Does reactance increase with an increase in inductance?
Inductive reactance case of ac) is equivalent to resistance (in case of dc) for inductors.
So if resistance increases current decreases
as well as if inductive reactance increases current decreases
What is rated break down voltage?
A: ZENERS are nothing else then regular diode that have a very predictable reverse breakdown voltage of xx volts. This voltage can be used to limit the input voltage or regulate on it.
1.) In series if 1 light bulb goes out they all do.2.) For each appliance to operate at its rated power, it must be subject to its rated voltage which corresponds to the value of the supply voltage. A parallel connection ensures that each branch is subject to the same (supply) voltage.
How many ohms are there in 12 volts?
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?"
A generator is used to convert what?
A generator is used to convert mechanical energy into electrical energy. It typically relies on electromagnetic induction, where movement (often from a turbine) causes magnets to rotate within coils of wire, producing electricity. This process allows generators to provide power for various applications, from small portable units to large power plants.
if a hen lays 10 eggs then the product of 1000 hens will be equal to 10000 meg ohms....
Scientist F.Wangdu....
What effect are there when resistance is increased in the size of the current?
Current is inversely proportional to resistance. If you double the resistance, you halve the current. Ohm's Law: Volts = Amps * Ohms Solve for Amps: Amps = Volts / Ohms
How long will a 100 amp hour battery with an inverter run a 42 inch lcd tv?
100AH * 12v = 1200 Watts of power.
A 16 inch TV has a power rating of 55w, so 1200/55 is 21.8 hrs
Your TV will have a higher wattage (usually on a sticker on the back) so sub in the the value...
I would also minus off about 10% as the inverter uses power itself, and bear in mind this maths is for an ideal world, ie, fully charged, brand new battery, no other sources of drain (lights, DVD players), average volume/brightness etc...
Why gravel used in transformer yard?
Nice Question:
It is done for 2 basic reasons:
1. If a flat or a concrete surface is used then there are chances of water accumulation during rain which must be avoided in Yards.
2. Lets suppose if there is any oil spill or leakage in transformer, then the oil can never got accumulated on surfaces. Instead, it will seep from gravel into bottom thereby minimizing chances of fires.
What happens when a 200 volt equipment is plugged into a voltage supply of 220 volts?
For more information see the answers to the Related questions shown below.
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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.
Give the function of its part of dc generator?
An AC generator generally called an alternator because it is generating a alternating current, consist of a rotor, field stator, slip ring assembly or rectifier bridge mounted in the place of the slip ring, in the case of a brushless alternator and an AVR (Automatic Voltage Regulator)
Why does the wire loop in an electric motor spin?
A clockwise motor runs clockwise because of the way it is made. It is designed to run clockwise because the designer has an application that calls for clockwise rotation.
A counter-clockwise motor runs the other way, again because of the way it is made. Many electric motors are reversible. If you are looking at something and it's clockwise - turn it over and it's anticlockwise!
What is the working of a switch yard?
A switchyard is essentially a hub for electrical power sources. For instance, a switchyard will exist at a generating station to coordinate the exchange of power between the generators and the transmission lines in the area. A switchyard will also exist when high voltage lines need to be converted to lower voltage for distribution to consumers.
Therefore a switchyard will contain; current carrying conductors, grounding wires and switches, transformers, disconnects, remotely controlled arc snuffing breakers, metering devices, etc.
True or false current is the voltage multiplied by the resistance?
False. Voltage (E) is the potential difference, i.e. electrical potential, in joules per coulomb. Current (I), on the other hand, is electrical charge flow, in coulombs per second. The two units are not related except through a common term such as resistance (R).
E = IR
I = E/R
R = E/I
What are the latest inventions in Electrical Electronics Engineering?
A new semiconductor material named graphene is invented by two researcher andrenove and konstantin novoselove. this will help us to makes the transparent screen or display.It is a another type carbon which is not used as semiconductor.
What is the use of ideal transformer?
Ideal transformer is useful in understanding the practical transformer..i does't have losses...
How do you calculate MVA rating of power transformer?
The product of the secondary rated current and the secondary rated voltage will give you the rated V.A of the transformer.
What is the difference between an ac with inverter technology and normal ac?
In theory, the inverter air con is more efficient in energy saving and temperature control. It's compressor motor is driven by direct current ( thereby a current inverter is installed in this air con) and its speed is variable. The compressor regulates the temperature by speeding up or slowing down the rpm of the compressor, just like a car engine in the highway. When the desired room temperature is reached, the compressor motor will run at a constant medium speed, just like a car on cruise control.
The normal air con regulates temperature by turning the compressor on and off. This start up process consumes 3times more electricity and the room temperature will also go warm to cool by about + or - 4 degrees during these process. In theory, the inverter air con is more efficient in energy saving and temperature control. It's compressor motor is driven by direct current ( thereby a current inverter is installed in this air con) and its speed is variable. The compressor regulates the temperature by speeding up or slowing down the rpm of the compressor, just like a car engine in the highway. When the desired room temperature is reached, the compressor motor will run at a constant medium speed, just like a car on cruise control.
The normal air con regulates temperature by turning the compressor on and off. This start up process consumes 3times more electricity and the room temperature will also go warm to cool by about + or - 4 degrees during these process.
What is the good slogan for science and tecnology?
Science and technology increase the Sociology......
