Electrical Engineering

No.

The kW rating of a transformer can be calculated by multiplying the kVA rating by the power factor. For example, if the power factor is 0.8, then the kW rating of a 100 kVA transformer would be 80 kW. You can also use the formula: kW = kVA x power factor.

V = I x R so current I = 1/2 amp. I bet the bulb is rated at 60 W because Watts = Current x Voltage.

Where V = voltage (volt)

I = current (ampere)

R = resistance (ohm)

Your question isn't easy to answer. A lamp has two 'resistances': a 'cold' resistance, and a 'hot' resistance. Before it is energised, it is cold, so its resistance is low; when it is energised, it becomes very hot, and its resistance increases significantly. So, the question is whether your '240 ohms' is the cold resistance or the hot resistance. If it is the cold resistance, then a current of 0.5 A will flow through it for a fraction of a second, then its resistance will increase significantly, and the current will fall to a very much smaller value.

To answer this question the voltage is needed.

That depends on the exact circumstances. For example, in electrical circuits, power = I2R. However, since the current, in turn, depends on the voltage and the resistance, it is better to express this as V2/R. For mechanical energy, power is basically speed times force.

The difference between a conductor and a insulator is that a conductor tries to keep the warmness away and the insulator tries to keep the warmness in. An insulator is like an refrigerator, and mabey a cooler so when you go hiking it keeps the coolness inside or keeps the warmness inside!!:-)<3

No system, Peak demand as defined by the Utility Co`s is usually 7am-2pm. During those times everyone is at work or school in larger buildings with larger systems creating this period of peak demand, essentially staying comfortable on someone else`s dime, and the programmable thermostat in the home would be in energy setback or unoccuppied mode. Or in some areas the Utility Co does this for the Homeowner via their own Energy Setback Systems or rolling Brown Outs if that is the answer your Teacher is looking for.

If they're connected one at a time ... first one and then the other ... then each one has 120 volts
across it while it's connected to the supply.

If they're connected across the supply at the same time in parallel, then of course they have the
same voltage across them, because their ends are common.

If they're connected across the supply in series, then the voltage across the 50-ohm load is 40 volts,
and the voltage across the 100-ohm load is 80 volts.

You must rephrase your question to make it more specific.

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The formula to use to find KVA in a three phase system is, KVA = Amps x Volts x 1.73/1000.

You should have about 230 volts between any pair of 3-phase service legs: L1-L2, L2-L3, L3-L1. If the voltage measured between any one pair results in low or no voltage, then you have a fuse or circuit problem.

Generally, 'insulators' are also called 'dielectrics'. But the term 'insulator' and 'dielectric' really refer to the properties of such materials. 'Insulator' describes the property of opposing current flow (or, strictly speaking, 'not supporting' current flow, due to its relative lack of charge carriers), while 'dielectric' refers to the property of supporting the establishment of an electric field which, in turn, acts to polarise its atoms and establish a (temporary) displacement current whenever a potential difference is first applied (or changed in magnitude).

The oldest theater in Serbia? Knjaževsko-srpski teatar is the oldest theatre in Central Serbia. It is based in City of Kragujevac, the fourth largest city of Serbia. The theatre was founded in 1835 by Miloš Obrenović, Prince of Serbia. In the time when theatre was founded, Kragujevac was first capital of the Principality of Serbia.

In a single phase electric motor, the centrifugal switch allows the start winding to be energized through the start capacitor when the motor is starting. This gives an out of phase magnetic field that, along with the in phase magnetic field from the run winding, helps the rotor to begin spinning. Once the rotor reaches a certain speed, the centrifugal switch changes state and cuts off the start winding. At that point, the motor continues running only through its run winding, and inertia keeps the rotor properly phase biased relative to the run winding's magnetic field.

By adding together the power ratings, and applying a diversity factor. A 'diversity factor' takes into account that not all loads will be operating at the same time.

capacitors can be used for many thing they are one of the most common electrical components they limit current differently at different frequency the higher the frequency the lower resistance. They can also be used to store voltage or build it up to be released all at once in a larger but than could be achieved other wise.

The generation of AC currents and relationship to frequency has to do with the speed of the unit that is turning the generator (prime mover).

The formula for frequency is f = Number of revolutions per minute of the engine (N) x Number of magnetic poles (P) / 120

Speed the prime mover up for a higher frequency, slow the prime mover down for a lower frequency. This is why the generator has to be wound for the voltage that it is going to produce and the frequency that it is to operate on.

This has probably got to do with Iron.

Most transformers consist of large amounts of iron that need time in order to change polarity of a magnetic field.

Faster frequency would make the transformer less efficient. The iron would not manage to become fully magnetized. Slower frequency would make the transformer need more iron, hence becoming heavier. If the size of the iron core were the same and we just lowered the frequency, then as soon as the magnetic field is buildt up, then the rest of the energy until next half wave will be transferred into heat.

It is simply a trade off between efficiency and practicality.

Today's high speed transformers operate at speeds between 20-80 Khz and is only doable due to a special core material of powdered iron that is much easier to magnetize.

Electricity in the early days was DC only. However, some decisions were made to use AC because DC is, at high voltages, very dangerous to humans, something that was demonstrated during the first few 'victims' of the electric chair that in the beginning operated at DC current only.

To install, maintain, and service electrical switch-gear, wiring, appliances, lighting (luminares), and related equipment. In most cases an electrician must be licensed by an authority (State or Provincial) and must ensure any installation or service work is performed to national, state/provincial, and local codes and ordinances.

You need alternating current for a transformer, for DC you would have to interrupt the power supply to make it effectively DC pulses.

no you must run a dedicated line

NO

Yes, with a caveat. The current ratings must be the same, the the 110V outlet must be a dedicated circuit, i.e. nothing else on that breaker. You can safely upgrade a dedicated 110V 15A circuit to a 220V 15A circuit by re-using the same wiring. You will have to just replace the breaker and the outlet. You cannot, however, increase the current load or have a 110/220V (4-prong) outlet. Note that if you move a non-dedicated circuit up to 220 you will start a fire.

I read this question as " I spent alot of money on a hot tub and I want to save money on the installation, so how cheaply can I endanger my family to impress them?" Call a professonal!!!...pkazsr

A 20 hp piston motor compressor at 208/230v appx. 50 amp running, and 100 amp locked rotor current, requiring 70 amp heaters. A rotary screw will demand apprx. 20% greater locked rotor, but about the same running, and perhaps 80 amp heaters. Halve most all for 460/480v.

A 12 - 15kva generator should suffice. If the budget will sustain, go for a 25kva.

The light bulb was invented by Thomas Alva Edison, and was a combination of different marerials and pure genious. He experimented with different materians and was left with the materials who transmitted energy best. he kept trying to combine these things, and whola, the lightbulb.

This breakthrough was not really recognised by the world at once. Many were sceptical, and some didn't understand the use of it. But after a while people saw the advantages of this invention, and it spread practically everywhere.

You'd potentially damage the meter. Whether you do or not is immaterial; if the meter cannot measure the range of voltages you are expecting, it will not give accurate readings over that voltage range, thus you should not use it. Buy a different meter that will measure over that voltage range, or use a voltage divider circuit to get a lower voltage at a certain ratio of what is actually in the circuit (this may be difficult to do, or very simple depending on the circuit tested - the key is you do not want to load the circuit with the voltage divider network).