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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 used to control voltage at a substation?
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, which permits finer adjustment.
The speed of the machine is tied to the power supply frequency and the number of poles the machine has. It becomes impractical to make a round rotor machine with many poles, so machines that spin at low revolutions will typically be salient designs. A two or four pole machine could be round rotor designs.
"AC 8" could refer to various things depending on the context, such as a specific model of air conditioning unit, a reference to a particular course or academic content, or even a designation in a sports league. Without additional context, it's challenging to provide a precise answer. Please provide more details for a clearer response!
One of the easiest ways to check for faulty devices and parts, is to use a multi-tester, sometimes called a multi-meter. Testing continuity by using the ohm setting will tell you if the connection through the device is complete or if it has opened and is no longer usable. For instance, if you place one of the test leads on one side of a fuse and the other lead on the other side of the fuse, you should show a short circuit or 0 ohms. If your meter shows infinite resistance, the fuse is bad and should be replaced.
ø means the Greek letter and numerical approximation
It is used to indicate the phase of a signal.
What is the purpose of the third wire?
By "third wire" I believe you are speaking of the ground wire. Its only purpose is to ensure that the over-current device, which is the breaker or fuse, operates property when a fault exists in the circuit. Without the ground wire you increase your risk of injury, death, or property damage.
It is there for your protection. Do not remove it. Always choose to use it when it exists.
In a-c current what type of load has a current in phase with the voltage across it?
A: purely resistive
What are the names of the different kinds of splices and joints used for electrical cables?
Some common types of electrical splice:
Rat-tail, Western Union, fixture, knotted tap, staggered splice.
Some common types of electrical joint:
Screw terminals, braided eyelets, crimps, sty-cons, plugs and sockets, insulated screw connectors, wire clip connectors (wire push-ins), twists inside wire nuts, plain wire soldered joints, soldered wire joints to posts and soldered legs for integrated circuits on printed circuit boards.
If no power is being delivered to a specific circuit when the breaker is on is the breaker bad?
Look very closely at the breaker, it could be in the tripped position. Compare the position of the handle in relationship with the other breaker handles. If it seems a little bit out of align move the handle to the full off position. You should hear the breaker reset if it was tripped. Move the breaker to the full on position, this should restore the circuit. If the breaker trips off instantaneously when moved to the on position, check what caused the fault and remove it from the circuit.
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(LIFE SAFETY WARNING! [disclaimer]
Electricity is dangerous!
You can be injured or killed!
Improper installations can cause fire, injury and death!
Troubleshooting is the height of the electrician's art...
The only reason there is "not enough voltage" somewhere is because there is a partially open connection providing resistance and a location to allow a voltage drop [bad splice, bad switch, bad breaker, broken wire, burned splice, ...].
It is the knowledge of how electricity works, and of the methods and materials used to create a functional wiring system, that enables a skilled troubleshooter to locate the problem and repair it.
Where should the "voltage" be, and how does it get there?
When you understand that, you will understand what is keeping it from getting where it should be...
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You can only answer this question by taking a voltage reading, using a voltage tester, from the neutral bar to the output terminal of the breaker itself!
This exposes you to dangerous voltages in an open panel!
TURN THE POWER OFF!
Call a licensed electrician!
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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.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure 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.
What the difference between single side band single carrier transmission and full carrier AM?
1. Single-sideband transmission requires only half as much bandwidth as double sideband.
2. SSBSC require less total transmitted power than full carrier AM
In full carrier AM, the transmitted signal consists of two sidebands (containing the transmitted information) and the carrier signal. Long ago, it was realized that both sidebands contained the same information, and the carrier signal could be supplied by the receiver. Thus, if you suppress transmitting the carrier and one sideband, you can use the available power to increase the power in the remaining sideband.
Is every resistance load resistance?
No. Load resistance is the value of the element actually doing the work of the circuit it is connected to. A speaker connected to an amplifier is the load.
The term, 'navvie', is short for 'navigator' -the name that, at one time, was given to labourers who dug trenches.
What is meant by sizing of electrical equipments?
Electrical equipment such as wiring, circuit breakers, transformers, and such come in many different sizes with very different characteristics. The transformer, for instance, that feeds your home is much smaller than a transformer that feeds a large commercial building. Wires that feed a toaster are much too small to feed a large air-conditioner.
When an electrical engineer designs an installation, he must decide what size each element must be. He must consider the voltage present to be sure the gear is rated to withstand that voltage. For instance, a panelboard rated for 208/120V cannot be used in a 480/277V installation. A breaker or fuse must withstand a certain instantaneous fault current that may range from a few thousand amperes to several hundred thousand amperes. Is the wire big enough to safely carry the current required? All these decisions and many more may be involved in 'sizing' the electrical installation.
What is the purpose of line trap?
A line trap is a set of physically-large inductors often seen hanging from transmission towers at the end of a high-voltage transmission line, where the line terminates at a substation. As transmission lines often carry data signals, which operate at frequencies very much higher than the 50-Hz (or 60-Hz) power frequency, the high inductive reactance* of the line traps act to prevent these signals from continuing beyond the end of that section of transmission line, while having an insignificant effect on the power-frequency load current.
(*Inductive reactance is directly proportional to frequency)
How the section of a transmission line can be used as lumped circuit element?
Actually in networks we will consider the elements like resistance, inductance, capacitance as lumped elements for simplicity, like this in power systems we will consider the transmission line parameters(resistance, inductance, capacitance) as lumped elements, because we will calculate all the parameters of power systems with respect to receiving end or sending end but not with respect to middle of the line. If a fault occurs on transmission line then we should not consider the lumped elements of that total transmission line, we should consider the lumped elements from sending end to the point where the fault is occurred.
What is a nonel and how it is different than detonating fuse?
Detonating fuses involve the use of electricity for initiating explosions. Nonel propogates a low energy signal along a chemical coating on the inside of a plastic tube to the main charge. Please see the link.
How can a 55kw motor running current be 27amps?
The running current of a 55 kW motor can be 27 amps if it operates at a specific voltage and efficiency. For example, using the formula ( P = V \times I \times \sqrt{3} \times \text{PF} ) for a three-phase motor, if the motor operates at around 400 volts with a power factor (PF) of about 0.9, the current can be calculated to be approximately 27 amps. This indicates a well-designed motor operating efficiently under load conditions.
What do you want to learn about or accomplish at work?
You want to accomplish whatever your work has set out to do. Learn whatever you need to learn to become a better worker so you can help provide for the community.
What are advantages and disadvantages of an electrical charge?
This seems like a question from an electrical course, and is probably best answered by your course materials.
It's your test question, not ours, and there won't always be someone to ask the answer of. Earn your diploma.
How synchronous motor can function as a synchronous condenser?
If a motor is spinning under no load, it is storing some energy in the rotating mass. This energy can be stored and released in the same way capacitors and inductors store and release energy. This is what a synchronous motor acting like a condenser is doing. The way it appears to the power system is dependent upon the field current applied to it. If used as a motor, this is controlled to keep it spinning at the desired speed under load. If used as a condenser, it is controlled to determine whether it will be releasing power ahead of or behind the power system (absorbing or releasing VARs).
Usually because the belt loosened, or the pulley is mis-aligned.
