Electrical Engineering

relate the new information to your prior knowledge

The electrical impedance of the windings would be so different running at 400 Hz instead of 50 Hz that the transformer's output voltage and current-carrying capacity would be very different to what it was originally designed to handle.

The only safe way to experiment with a transformer that was designed to operate at standard mains voltage and frequency would be in an electronics laboratory.

In a laboratory a safe method of operation and the right equipment and test instruments could be used. The method would probably be to vary the transformer's: * load, starting from a high resistance value,

* supply voltage, starting from zero, and

* supply frequency, starting from 50 Hz so that the resulting output voltage and current could be measured. The test results could then be compared with theoretical calculations of what the effects are likely to be of using a supply frequency of 400 Hz instead of 50 Hz.

op amp can perform mathematical operations such as summing,subtracting differentiating,scaling,integrating which an amplifier can't perform. hence op is called as op amp & not just an amplifier.

opamps were originally designed to perform mathematical operations in electronic analog computers.

LILO is Line In Line Out. If a new EHV substation is inserted between two existing substaions, the transmission line for new inserted EHV substation is called LILO i.e. Line In Line Out. When a transmission line is passing nearby to a substation or generation station to tap it, the system used is called LILO. While using this system , one bay is required for incomer and the other is outgoing. The power is drawn or added as per requirement. It may also be called Loop In Loop OutSP.

the sprrd regulation is cnsiderably improved.

The answer depends entirely upon the scenario. Are you dealing with AC or DC? Does your circuit contain passive components or both passive and active components?

For example, if you a simply dealing with a resistive DC circuit, you can derive your answer from Ohm's law, V = IR. Rearranging for current, I = V/R, so if you double the voltage, the current is subsequently doubled.

The automatic Air Brake was invented by Granville Woods

It is connected in parallel and measures potential difference.

The basic rating is continuous current, the value of amperes intended to flow through the device. (This is sometimes described as "operational current" or "thermal current.") When we speak of a "100 ampere fuse," for example, we mean that a load drawing 100 amperes continuous current is the maximum for which that fuse is intended to provide fault protection. How long is "continuous"? "More than three hours," according to one definition. Although we tend to think of "inductive" and "resistive" circuits as two separate entities, the distinction is only one of degree. Whether a-c or d-c, all real circuits contain both resistance and inductance. Opening a current-carrying circuit will therefore always result in an arc across the opening contacts. How intense-and therefore how damaging-that arc may be depends upon the relationship between resistance and inductance, expressed by the circuit power factor.

Current ecowas headquater

A SYSTEM is any active device if left as open loop it will saturate one way or the other if the gain is ample. To control a system it must have some feedback to determine ts linear operating capabilities. As an example an airplane taking off at las Vegas the cabin will be pressurised to -1000 feet from the ground and maintain a rate of climb to even 50.000 feet with a delta of 17 PSI The cabin pressure as a system will maintain this delta by close loop control otherwise we will need oxygen if flying. INTERESTING?

According to BS 7671:2008 'Requirements for Electrical Installations', 'high voltage' is defined as (for a.c.) exceeding 1000 V (a.c.) line-to-line, or 600 V (a.c.) line-to-neutral.

RATIO ERROR The secondary current is less than the expected value. The secondary is less in magnitude. This diffence is known as ratio error. PHASE ERROR The angle between the expected and actual secondary current is known as phase error.

You know there is a differnce. The dynamic short circuit is dynamic and the static short circuit is static. It's common sense really.dyanamic means when due to some external source theresistance becomes zero ,can be through anythin due to high supply of current or anything,the current in that circiut becomes infinite and that result s in short circuiting. Static short circuit means when through the different changes in the voltage makes the resistance zero and current infinite ,

V = I/R

WHERE R= 0

AND CURRENT BECOMES INFINIT AND THAT RESULT IN A

SHORT CIRCUIT

Smoke. Since a voltmeter is in parallel with the load it is right across the source voltage. Putting the amp meter across the line with its low resistance it will act like a fuse, hence the smoke. Newer solid state testers are usually smarter that the operators. They have built in circuitry which sense the wrong settings you are using and shut the tester off with a "beep" to let you know that you are doing something wrong.

You can expect it to burn out the piece of equipment it's attached to. Maybe not right away, but fast enough.

Supplies are nearly always 50 Hz or 60 Hz. India's choice of 50 Hz probably goes back to the days when India took its technology infrastucture from the UK, so they probably imported the choice of 50 Hz at that time.

Every electrical device plugged into a wall-socket in your house,

as well as every socket with nothing plugged into it, is in parallel

with every other one. The only series-wired electrical devices in

your house are the light-switches.

where can I buy a TYC50-12 synchronous motor for a fibre optic christmas tree

It is wise to start thinking of power in DC circuit. If a load is connected to a power source in a DC circuit, the corresponding VOLT CURRENT plot both will be in the positive quadrant. Of course, polarity must be correct. Now if the CURRENT (in the same polarity arrangement) happens to be in the negative quadrant, the power is said to be reversed.

The same can be thought in an AC circuit. Taking a half wave cycle of both VOLT and CURRENT, one can apply the same understanding as in the DC circuit.

If the AC circuit is capacitive or inductive, VOLT and CURRENT waves will be shifted according to the value of the capacitive or inductive load, and here one has to be aware.

Adel Aljassar

adel@al-jassar.net