Electrical Engineering

It depends on the equipment. The power supplies on most devices can only handle a specific voltage and still work properly. Some, for instance some cell-phone chargers, can handle a range of voltages, say from 110 to 240, which lets them operate in both the States and the UK (where the standard home/office voltage is 230 Volts). Check the label on the back of the device; it will usually show the operating voltage required. Asking the maximum voltage for 110 equipment is valid. 110 means AC voltage that averages 110 volts as it swings above and below 0 volts. The label on a device typically will not tell you the maximum voltage it can withstand if it is plugged into a U.S. 110 volts AC outlet.

U.S. houses are wired with 2 hot wires (each 120 Volts AC but opposite of each other) and a neutral wire (0 volts). That way electrical outlets can be wired for 120 Volts AC if they use a hot wire and the neutral wire... or 240 volts AC if they use both of the hot wires.

If the neutral line goes bad then the 120 volts AC outlet floats anywhere from 0 volts to 240 volts. I have been in a house when this occurred (the neutral corroded on the transformer that fed several houses). Supplying too high a voltage burned out an air conditioner, a refrigerator, and an incandescent bulb actually burst, scattering glass close to my wife. The air conditioner threw out a lot of smoke so there was a danger of fire.

In the U.S. a typical 120 volts AC circuit often has a higher voltage. I have seen specifications and codes that put an upper allowable voltage at 120 volts AC, 137.5 volts AC, and 150 volts AC. Every electrical device has different limits but I would not subject anything built for 120 volts AC to voltages higher than 132 Volts AC unless I had specific knowledge that the device could handle the higher voltage.

Phases in AC refer to the number of sine waves of alternating current used to generate the average voltage. In 2 phase, two opposing sine waves are overlapped to give the average voltage delivered, eg 240V in household supplies.

In 3 phase, three sine waves are overlapped to produce a more consistent average voltage.

If a DC supply is connected to the incomer of a transformer, you effectively have a short circuit, because the DC impedance of a transformer (actually, any inductor) is quite low. You will blow something.

A transformer winding only produces a magnetic field when current flows through it. Switch the current off, and the magnetic field disappears. You do not need to 'demagnetise' a transformer winding.

Quite simply, so you don't put too much current on the wires than they can handle. They also provide protection from 'ground faults', which is when the 'hot' and neutral wires touch. This causes a spike of current (because the resistance drops to near zero) and the breaker senses that too, or it should when it functions properly.

To allow room for oil expansion and contraction. The transformer is completely filled with the oil and when it heats up under load or due to ambient temperatures, the oil has to have a place to go. In the event of colder weather or if the transformer is not under heavy load the oil cools and contracts creating a slight vacuum inside the tank. The conservator acts as a reservoir of oil that can then flow back into the tank so that no air enters it.

The stator and rotor of a machine are not made from sold pieces of metal. They are constructed by clamping stacks of thin sheets of silicon steel, called 'laminations', together. Laminations are essential to minimise circulating currents due to voltages induced into the core/rotor when the machine is operating. These laminations are created by a stamping machine, which cuts the required shape from large sheets of thin metal.

CT ratio is the ratio of primary (input) current to secondary (output) current. A CT with a listed ratio of 4000:1 would provide 1A of output current, when the primary current was 4000A.

Voltage is the electrical potential difference between two points.

The armature has the stationary (not physically moving) magnetic field, which attracts the magnetic field in the rotor. Since DC does not alternate, a split ring is used to alternate the current (and resulting magnetic field), so that the rotor will spin.

due to the extension of loads they are using the relays for protection.........

you can get an idea by looking at the insulators

they must function in rain or snow

dew can collect on the insulator

they are made of porcelain with a glazed surface

3" diameter gives about 3" length of dew coated glaze and is safe at about 5000V

so if the insulator has 3 skirts its about 15,000V

10 skirts about 50,000V

the drops to the houses are low voltage and may be as little as 1/2 of glazed surface 600V or less

The power consumption is the same in both cases. For a high-power motor it is more efficient to feed a 3-phase motor because the amount of power wasted in the wiring that feeds the motor is less, assuming the same size of wire.

An emergency generator is attach to a location power supply and electricity. When the power supply or electricity shuts down unintentionally the emergency generator will send power to the things that it is attached to that is designated, until the main power is back on.

The causes of over loading in generator comes from the action of applying more load that the generator is rated for. An example using a 5000 watt generator and a connected load of 6000 watts.

110 vs 230 Vac - The lower voltage is safer, but requires more current and larger wires. (BTW, the transmission loss is not worse because of 110 Vac because everything is distributed at much higher voltages, it only becomes 110 at the transformer near your home).

60 vs. 50 Hz - The higher frequency allows for the use of less iron in transformers and motors, but at the cost of more losses in the distribution system.

The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being comsumed. Using LCR meter to determine these 2 values of each winding 1) DCR 2)inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted. The symptoms of an interturn fault are loss of power output (blown fuse) and distortion as in audio power transformer. In power transformer there will be excessive heat as power is being consumed. Using LCR meter to determine these 2 values of each winding 1) the DCR 2) the inductance. Compare the value obtained with a good one. There should be some differences in DCR and particular noted the low or no inductance in case of interturn shorting as if output winding is being shorted.

The question has to be more specific. Full load amps, watts or voltage. Please restate your question.

There are two types of power - real power and reactive power. Real power is power that is used, such as the power used to light a light bulb. Reacitve power is power that is held and released by a reactive element (capacitor or inductor), thus is not actually used to do any work. The reactive elements cause a phase shift between voltage and current, which manifests itself as a change in power factor.

Power companies must supply both reactive and active power. Total power is equivalent to sqrt( Reactive^2 + active^2). Not only do they need to supply the reactive power, their equipment must be sized to handle a larger total power. Reactive power is generated by installing extra equipment - capacitor banks or inductor banks - or by running generation in such a way that more reactive power is created (this will lower the power plants' real power output).

Depending on who the customer is, they may not be billed for the reactive power, thus the oversizing of equipment, and the supplying of reactive power does not generate any revenue (but costs them). If power factor is bad enough, the power company will lose money, and thus require power factor correction, or will bill on both real and reactive power usage.

It's simple economics (money)!

That might be to make it run the right way.

It depends how they are connected. If they are connected between line conductors then they are measuring line voltages. If they are connected across phases then they are measuring phase voltages.

Stabilise the arc and optimize the operation of the furnace.