Electrical Engineering

EOL terminology is also related to fire alarm systems. It is the end of line resistor that is in each pull station loop. It is used to put a load on the circuit so that each circuit draws a current. This in turn is how a trouble is monitored, if the circuit gets opened a trouble alarm will sound notifying maintenance that the circuit is inoperative. First thing which I am familiar with, which kinda goes back to the "older" days, is that EOL = End Of line. The term is largely archaic outside the bounds of mainframes.

For home computers, the "EOL" is usually "LF"+"CR", or linefeed (advance to next line) + CR (archaic but still in use - Carriage Return, which moves the cursor to the beginning of the line), thus "LF+CR" is used most often in DOS and Windows applications while some applications and/or operating systems treat just the "CR" to mean both... Go to next line AND go to the beginning.... basically the exact way the CR on a typewriter works. Hitting "CR" on a typewriter both advances the paper one line, and moves the carriage, or "typing spot" to column one.

Wow, the old days... heheh

This is the current level needed to energize a transformer to its rated voltage
The clue is in the name! 'Excitation' means to create a magnetic field. So the excitation current is the current drawn from the supply which sets up the magnetic field around the core.

For DC circuits:

R = l*p / A

R - resistance

l = length of the conductor

p = electrical resistivity

A = the cross sectional area

Calculating for AC, and especially three phase power becomes much more complicated. If you need to know more for AC, let me know specifics.

coaxial cable

he factors affecting the speed of a d.c. motor are, 1. The flux Φ

2. The voltage across the armature

3. The applied voltage V

Capacity for cable 70mm (143-212 amp) and may vary depending on installation method used.

Voltage will be same in all branches.

Voltage= Current * Total Resistance

A shunt generator is a machine with a rotating set of coils of wire embedded in the iron core in its armature (the spinning part), and a 'commutator' and brushes that carry the current from the (spinning) windings on the armature to the stationary external electrical load. It also has a 'field' winding that creates a stationary magnetic field inside the machine, that the armature coils are spun in. As the windings spin, they cut the stationary field and generate an alternating voltage. As well as providing a moving connection to the coils, the commutator and brushes act like a switch, reversing the connections from the coils to the external circuit each time the waveform changes polarity from positive to negative and vice versa. This creates direct current in the external circuit and load.

In a shunt generator, the field windings are connected in parallel with the armature ('shunt' is a common term for 'in parallel') and the field gets its power ('excitation') from the armature - the machine is 'self-excited'. A self-excited generator needs a small 'residual field' in the field's iron core so it can generate a small output from the armature when starting, which is fed to the field, boosting the armature output, which is fed to the field.... and so on, until the field iron core saturates with flux, and the field stops strengthening.

Shunt generators are the 'workhorse of the small generator market - they are cheap and simple, have an output voltage that 'droops' a little with increasing load, and most shunt generators can safely be short-circuited - this takes the electrical energy away from the field, and the armature can usually develop only a small output current - not enough to damage it.

If two 1-ohm resistors are connected in parallel, their resistance is 0.5 ohms. If they are connected in series, their resistance is 2 ohms. It is not possible to connect only two resistors in series parallel.

Impedance (Z) voltage is the amount of voltage applied to the primary side to produce full load current in the secondary side. It is usually listed on the transformer nameplate, expressed as a percent, and measured by conducting a short circuit test.

1. By using transformer oils.
2. By nitrogen or sulfur hexaflouride gases.
3. By using flourinated hydrocarbons
4. Case is wide corrugated
5. Case is provided with radiators

In measuring high AC currents a current transformer with a suitable rating say 100/5 or 1000/5 are used. The secondary current is usually 5 amps when the fulload current of 100 or 1000 as the case may be is flowing in the mains. It is the univerasl practice to use CT's for measurement of AC currents. In DC circuits the transformer method will not work, so to increase the current that you can measure you can allow a known amount of current to bypass the ammeter and recalibrate the ammeter. In other words, put a shunt in parallel with the ammeter.

It means to have an orgasm and it usually refers to men having an orgasm.

I don't know how you got this posted in the Dodge forum but I will explain.

The directional overcurrent relay is a relay that will provide overcurrent protection in a directional manner. I know this sounds simplistic but let me give you a scenario.

A large industrial company has its own electrical generation provided by a few generators. One might think that the company would have no outside connection to a public utility because they generate their own electricity.

However this is not the case as having a tie to the utility affords a few advantages. Some advantages are that synchronization of the industrial companies generators can easily be maintained at 60Hz. Additional inrush current can be easily provided by the utility, whereas should the industrial company only rely on their generators a larger voltage swing might occur when a large motor is started. The industrial customer can also be provided with backup power levels in case of some failure with their own generation.

So you do want to provide a tie to the utility. You must protect the tie against overcurrents. However, if something were to happen to cause the utility power to fail you certainly do NOT want to try to power all the utilities other customers.

Thats where the directional overcurrent relay comes into play. It will allow power to flow and protect a circuit as long as power is coming into a plant by a tie line. However should power try to flow out of the utility tie the directional overcurrent relay will trip.

A mechanical directional overcurrent relay is actually a combination of a directional relay and an overcurrent relay. The directional portion is closely resembles a watt-hour meter. A potential transformer is required to provide a reference and if current is flowing one direction then a positive torque is placed on a mechanical disk. If current is flowing in the other direction then a negative torque is placed on the disk.

Should the CT and PT connections be made such that positive torque is placed on the disk when current is flowing out of the industrial customer and to the utility then the disk will rotate and cause a contact to close. The closing contact will operate a breaker trip coil. However if current is flowing from the utility to the industrial customer then negative torque will be placed on the disk and it will be stopped by mechanical stops and the breaker will continue to remain closed.

Of course you can use normally open or closed contacts to make the relays operate when and how you want.

Other applications are as a reverse power relay for a generator and for line protection in a grid type system.

The hazard is electric shock, flasover, short circuit, fatality. Care should taken to use right tool for roght application. The tool must sutably insulted. The person using the tool must be qualified and trained to do the said job.

If I am not wrong then you have asked about a transformer. And its a current transformer. By theory of voltage transformer we know that

Vs/Vp = Ns/Np

So for answering your question we need the value of number of turns in primary and secondary coil. But you can use this equation to find your answer if you have other values. By using ohmic law you can convert voltage to current.

MCBs are more convinient because when an excess current passes through it or a short ciruit occurs it just trips off and can be resetted after the fault has been solved, while the fuse just blows off(melts) when a fault occurs and it needs replacement everytime it operates.

It depends entirely on the motor design. The only universal disadvantage of a DC motor (vs. an AC motor) is the need for a DC power supply (DC power is more difficult to transmit efficiently over long distances, hence the use of AC for typical power grids).

Typical brushed DC motors (the cheapest and hence one of the most common type of DC motor) tend to wear out eventually due to friction and draw MUCH higher current when stalled than when turning, which can cause overheating. They are also typically heavier than AC motors with similar specs. Of course all of these problems can be eliminated by using a (slightly more complex) brush-less motor design.

Resistance is directly-proportional to the length and resistivity of a conductor, and inversely-proportional to its cross-sectional area.

So a shorter wire would have less resistance than a longer wire made from the same material, and a wire with a greater cross-sectional area would have less resistance than one with a smaller cross-sectional area made from the same material.

Resistivity depends on the material from which the wire is made, with some materials being better conductors than others. For example, silver has the lowest resistance compared with other metal conductors having identical dimensions. Similarly, a copper wire will have a lower resistance than an aluminium wire of identical dimensions.

a polarity test is a test which use to check the polarity of tranformer.the rision of this test to running the two or more transformer in parallel.like bettry situation or to fin the terminals

There are many causes of power failures in an electricity network. Examples of these causes include, faults at power stations, damage to power lines, substations or other parts of the distribution system, a short circuit, or the overloading of electricity mains.

1mva = 1000kva so you simply divide by 1000.

10000KVA = 10MVA

K = kilo = 1000

M = mega = 1000000

A current source varies the output voltage to maintain the desired current. A voltage source has a constant output regardless of the current draw (up to the capacity of the supply, of course).

Capacity in Ah is not directly related to voltage. If you have 3 AA batteries, each with different mAh ratings, you should be able to connect them in parallel or series to your hearts content. In series, the voltage will be additive: 3*(1.5volts) = 4.5 volts total voltage across all three batteries in series, assuming the battery voltage is 1.5 volts. In parallel, the voltage will be equivalent to 1 battery. In parallel, the three batteries are able to provide 3 times more current at 1.5 volts than if all three are in series at 4.5 volts.

Be careful when parallelling batteries of different voltages though. This is not a good idea, as they will try to force each other to match terminal voltage (voltage at the outputs of the batteries). An example: 1.5 volt AA battery, and a 12 volt car battery can be put in series - the total voltage will be 13.5 volts. The total current that can be sourced will be limitted by the AA's limit (much less than the car battery's limit). If put in parallel, the AA will try to force the voltage of the car battery down to 1.5 volts by drawing current into itself from the car battery. Alternately, the car battery will try to force the AA to 12 volts by pushing current into the AA battery. The AA battery will overheat, and likely catastrophically fail (blow up).