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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

How does temperature affect resistance of a wire?

If you are asking if a hot wire has a greater resistance than a cold wire then the answer I would say is yes. Cold wires have always had less resistance than hot wires

What happens if commutator of DC generator is removed?

If the commutator is removed from your generator, you (if you connect slip rings) get AC supply instead of DC supply. the function of the commutator is to convert AC to DC supply and vice versa.

Additional Answer

Removing the commutator will also prevent you from connecting the output of the generator to its load. Remember, the generator's armature is spinning!

In the setup function of Arduino how do I average 50 readings to determine ambient light level and save the average voltage in the variable Vref?

You can use a FOR loop to loop 50 times, add the reading to a variable and then divide by 50 after the loop completes to determine the average. Make sure that you use a variable type large enough to keep the total. Keep in mind that unless you put a delay in the loop the 50 readings will be taken very fast and will probably vary little. You need to consider what a reasonable time to measure to determine what a good average would be, and then add a delay to give you the right period to take the average over. For example, if you want to take the average over 5 minutes (300 seconds), you would need to add a delay(6000) 6 seconds) to stretch it over the measurement time. Keep in mind that your main program loop won't start until the setup process is complete, so in this example the setup process will take five minutes.

Electrical equipment that is defective should be?

Electrical equipment that is defective should be where possible repaired and if not repairable it should be replaced.

Why would you megaohm a motor?

To determine whether there are any electrical shorts among windings, or from windings to case ground.

Why delta connection is made in primary side of step down transformere?

not necessarily

if the power source is delta the y voltages (or phase to ground) may not be predictable

there is 3phase delta with one leg grounded

there is 3 phase 240 delta with center of one phase grounded for 120/240 single phase for lights

primary on these is all 240 delta

y would be 0 120 132 240 or 277 depending on that ground point

What happens if the relative speed between the rotating flux of stator and rotor of the induction motor is zero?

if the relative speed of magnetic flux of stator and rotor becomes zero there will be no back emf and eventually the rotor gets zero speed

When choosing a mov?

If you are asking about MOV as in a Metal Oxide Varistor, then you choose the value at the point of clamping.

If your circuit is built for 120v, but you obviously derated your components, so they should survive to around AT LEAST 150v.

So you would choose a 150v MOV.

The MOV is a path to GROUND.

In normal operation, the MOV does NOTHING!

It is a closed valve (or OPEN circuit)

When the voltage on the line reaches the MOV's rated voltage, 150v in this case, the valve opens (circuit closes) and gives the spike a path to ground, instead of through your circuit.

Here is a link to surge suppression in general and includes MOV's:

http://www.naturalhandyman.com/iip/infelectrical/infsurgeprotect.html

What happens when a 70 amp hour battery is connected to a 50 amp hour charging circuit voltage of both batteries are being same?

The 50 amp charging circuit will never be able achieve a full charge for the 70 amp hour battery, thus in effect turning the 70 amp hour battery into a 50 amp hour battery.

If you attempted to read the voltage across a car battery with the multimeter accidentally in ammeter mode?

A multimeter when used on voltage, has a very high resistance/impedance to limit the current flowing through it. However when you set it to read current, it has a very small resistance to encourage the current to flow through the metre so can be measured. So ig you put a multimeter across a voltage source (in parrallel) when its set to current, you will normally destroy the metre. Although more expensive metres will have a fuse to protect the instrument should this occur. Hope this helps Always switch back, should you do this on the mains, you can quite easily set the metre on fire!! CB Eng

Is the number 5 cylinder on a jaguar where is it in the front of the motor or the back of the motor?

closest to the driver is the highest cylinder, also everyone should have a manual for their vehicle, and the library should have a professional shop manual available in the REFERENCE section...make copies of the right sections...good luck :)

What is ammature resistance?

Right now a DC engine is begun the armature is stationary and there is no counter EMF being produced. The main part to cutoff beginning current is the armature resistance, which, in most DC engines is a low esteem.

High repetition resistance training Innervates high threshold motor units?

Does not innervate high threshold motor units and limits the potential for Type IIB muscle fiber hyper

On an average how many times you can use RFID tags?

The type of RFID tag you are referring to is likely a passive device. It gets read by stimulating it with a certain RF frequency and then looks for a unique return. Hence the tag life is essentially forever.

What is Pure Resistive?

A purely resistive load is one in which there is no capacitive or inductive reactance. Whe driven by an AC voltage source, such a load will have no shift in phase angle between voltage and current.

How is the power factor of an Electrodynamometer type wattmeter improved?

Power Factor of an electrodynamometer can be improved by connecting a large resistor in series with the current coil.

What is Corona power loss in transmission line?

Corona Fields arround a transmission line is the high electric field caused by the transmission line causing the surrounding air to ionise and conduct electricity. As this ionisation requires a current to maintain, this causes a loss associated with the corona.

Why is voltage always stepped up and stepped down in multiples of 11?

The reason is some thing historical. In olden days when the electricity becomes popular, the people had a misconception that in the transmission line there would be a voltage loss of around 10%. So in order to get 100 at the load point they started sending 110 from supply side. This is the reason. It has nothing to do with form factor (1.11). Nowadays that thought has changed and we are using 400 V instead of 440 V, or 230 V instead of 220 V.

What is meant by 220 KV in 220 KV three phase Power Transmission line?

KV is the abbreviation for kilovolts. The prefix kilo means thousands, so 220 kv means 220 kilovolts, or 220,000 volts.

How could you determine whether a string of lights is in series or parallel?

on applying same power the one which glows brighter is the one connected in parallel connection.