Electrical Engineering

V = IR

= 8x10-3 (8 mA) * 10x103 (10k)

= 80v

If a motor is connected in a star configuration it will operate at a slower speed. This is the working process that a star delta starter operates on. At first through the starter the motor starts in the star connection. When the motor gets up to its highest speed in that connection it times a timer out , the star starter drops out and the delta starter pulls in and then connects the motor in the delta connection. This allows more voltage to be applied to the motor and it then speeds up to its nameplate rated RPM.

A slip ring motor contains a slip ring, which is a mechanical device that transmits power and electrical signals from a stationary to a rotating structure. They are commonly found in engines used in cable reels, wind turbines, packaging machinery and radio telescopes.

A transformer is a device that converts electrical power to a different voltage and current potential. You may have one at your home that converts the 110-120 volt wall output to 6-12 volts. The input voltage is stepped down to a lower voltage; the input current is also stepped up by the same factor as the voltage is stepped down.

It reads 100, 250 1,000 DC for both 200MΩ and 2000MΩ ranges.

Power factor occurs because we switched from DC to AC. In earlier days we used DC and then after invention AC there occurs power factor. Because in DC there is no frequency and there will be no angle difference between voltage and current. But in case of AC there is frequency and there may be some angle between Voltage and Current. But if we use pure Resistive elements there will not be angle difference. But in most of the industrial process, the loads are inductive(majority) So there will some angle difference between voltage and current and this leads to power factor since we know that power factor is a cosine angle between voltage and current.

If it's a simple resistive circuit, or a D.C. circuit, 1 kVA = 1 kW. Generally, it depends on your power factor. Since real power, P, is equal to the total power, S, multiplied by the power factor, p.f. Power factor is the cosine of the angle between the current and the voltage, O. So,

P = S * cos(O)

V=I*R

Where:

V is voltage

I is the current in ampers

R is resistance in ohms.

So, if the current is 15 A and the resistance is 5 ohms, then the voltage must be 15 A *5 ohms = 75 V.

Inability to synchronize power generators either means you are doing it wrong, or there is something wrong, some malfunction.

Synchronization procedure depends on the particular design, but the generalized procedure is to match voltage and RPM, with the second (to-be-synchronized) generator slightly higher in both voltage and RPM, and close the circuit right at the point of synronization as indicated on a synchronometer. Immediately after closing the circuit, you want to bring the excitaion voltage and power input up, so as to take load, otherwise the second generator will become a load instead of a generator.

This procedure works in the normal case where the first generator is much larger than the second generator, i.e. the first generator is a power distribution grid. Cases where two equal generators are being synchronized are different. Again, consult the documentation.

If the procedure is being followed correctly, then you need to troubleshoot.

1 HP=746 watts 15 HP=11,190 watts Ohm's Law says Current (in Amps) = Power (in Watts) divided by Voltage (in Volts) 11,190 watts divided by 415 volts = 26.96 amps.

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For a three-phase motor each phase supplies one third of the power, so that is 5 HP on each phase. A 415 v supply has a line-to-neutral voltage of 240 v, and 3730 watts would therefore required 3730/240 amps, or 15.54 amps.

However due allowance must be made for (i) the power factor and (ii) the conversion efficiency. This would increase the current by an estimated 20% so the current is therefore estimated to be 19 amps.

Very generally, a closed-loop system will have some form of feedback that regulates the system behavior, whereas an open-loop system does not have this feedback.

As a simple example, imagine you driving a car on a freeway: your car enters at 50 MPH and you want to be driving at 65 MPH. You know that if you depress the pedal at a certain degree for a certain amount of time, you will eventually accelerate the car to 65 MPH. In an open-loop system, you would have to make the best guess for the angle and amount of time you need to depress the pedal. In a closed-loop system, you are watching your odometer in order to see that you've actually increased your speed to 67 MPH and need to lay off the gas a bit.

More importantly, if your car encounters a hill your closed-loop system will be able to recognize the fact that you require more acceleration to maintain your speed, whereas your open-loop system might slow down a lot.

It should be clear from this example that closed-loop systems are in general more robust to changes in the system state that aren't considered in your model.

Get a charging kit from an auto parts store. This should include a gauge (or gauges) and freon. Your '98 uses the new type of freon so you don't have to worry about conversion. Follow the instructions on the kit. You will need to locate the charging ports (high and low side) and put the proper amount of freon in the correct port until you reach the right pressure. You'll need the engine running and the A/C on high while you do this. Don't overcharge - you need to use a gauge.

By Ohm's Law, current is voltage divided by resistance, so a voltage of 6 volts across a resistance of 24 ohms will develop a current of 0.25 amperes.

Because a short allows/causes very large current flow, which "overloads" the wire [conductor]. When a conductor [wire] carries much more current than is safely capable, then the conductor heats up, and can cause enough heat to ignite the insulation and adjacent combustible materials on fire.

If the load is connected in wye (star) and it has a neutral, then the vectorial-difference of the phase currents will flow in the neutral and there will be no problem. On the other hand, if there is no neutral, then an unbalanced load would cause unbalanced phase voltages.

There is no answer to this question. It could be anywhere between 2.5V and 12V. If you connected them in series the answer would be 20.5V, in parallel the higher voltage battery will discharge into the lower rated cells, the resultant voltage is dependent upon the internal resistance of each of the batteries. In practice you wouldn't do this, so it's either a mistake or trick question. www.powerinspired.co.uk

yes,infact every diodes have certain limitations.The maximum value of current that can pass through it will normally be encrypted on it usually at the time of manufacture.

It really is. A tiny solar panel collects sunlight, which then creates an electrical current. This current passes through a tiny electromagnet, which cause a switch to be held open so that power can't get to the light. When the sun goes down, power is no longer being created at the solar panel, which in turn causes the electromagnet to stop being magnetized. This causes the switch to close, which then cause current to flow to the light.

yes

the current can flow through a short circuit but there is no voltage because of the zero resistance

hence current through the circuit will be infinite

The above is of course a strictly theorethical truth. In the real world, several things limit current. The power source has a finite capacity, sometimes expressed as internal resistance, sometimes in max current, etc. All the wires, connections, and switches also have resistance. At high levels of current like this, even a small resistance will introduce a significant voltage drop. Use Ohms law, and you'll quickly see that with small amounts of resistance, infinite current isn't a real world situation. Likewise there will always be a certain small voltage, otherwise, there could be no current..

Yes that is why most factories or business that use motors, utilize 3 phase service. There also is much less current draw relating to expense in electricity rates.

As a general rule, 3 phase devices use less electricity relating to current usage.

Power (P) = Voltage (V) x Amperage (I)

Written as

P=VxI

or to find Voltage

V=P/I

Voltage is measured in Volts (V)

Amperage is measured in Amperes (Amps or A)

Power is measured in Watts (W)

A 'core type' transformer core is one in which the primary windings and secondary windings are placed around each of the limbs, as opposed to a 'shell type' core, in which the two windings are placed across the centre core. A core-type core is a magnetic circuit equivalent to an electric series circuit, whereas a shell-type core is equivalent to an electric parallel circuit. This is better answered with a diagram, so I suggest that you do a search on the internet.