Electrical Engineering

It is in some places, but not generally because it requires at least 3 wires, and can only transmit 2/3 of the power of an equivalent 3 wire, 3 phase system.

maximum demand is measured in kva because current drawn is dependent on power factor for the same load and current drawn is calculated with kva

Schematic or Circuit Diagram.

An artificial neutral is crated in the CT of the line to be protected (for transmission lines) a CT is fixed in the neutral of the CT. if there is any imbalance in the 3 phase current then the relay will develop a difference in neutral.that can be sensed by the CT,then gives the trip command to relay

You have it backwards, the resistance controls the current not the current controls the resistance. I = E/R . Your question should read, "If the voltage is constant and the resistance in the circuit is increased what happens to the current?" Say the voltage is 120 volts and the resistance is 30 ohms, I = 120/30 = 4 amps. Now we double the resistance to 60 ohms, then I = 120/60 = 2 amps. So now you can see if you increase the resistance the current drops.

First determine what voltage is needed for phase to phase. Where you work on or where the gears are coming from would help to answer this question. In Southeast Asia, where power is 220~240 volts, a 3 phase system would be 415v phase to phase. In North america, a 3 phase system would be 208v phase to phase. So now you know the voltage that you are working with on a 3 phase system. Next use this formula, kVA x 1000 / voltage required / 1.73 = amp 3 phase Example, you have a 60kVA generator. And you working in North America, which is 208v phase to phase. 60 kVA x 1000 / 208 v / 1.73 = 166amp 3 phase Written by: Rony Xu Hope this helps!

Overhead lines are uninsulated, as they depend upon the air to provide insulation. However, they must still be insulated from the towers or poles from which they are suspended. This insulation is provided using glass or ceramic insulators. The greater the line voltage, the longer the ceramic insulator, or the greater the number of glass insulator 'dishes'.

you keep the hv & lv on the dyn11 tx straight in phasing. you then put a cross on any two phases on the hv side of the dyn1 tx, and do the same cross with the phases on the lv side of the tx. for instance lets say we cross a & c phases on the hv & lv sides of the dyn1 tx. now draw a diagram with the four tx, split them up, 2 x dyn1, 2 x dyn11. now on the diagram where you have dyn1 tx, change the the phase plates to read cba left to right, also change the lv side to match. leave the phase plates on the dyn11 tx alone to read abc left to right on both sides. now draw the cables going between them on the hv & lv sides. now if a phase always goes to a phase and b & c phases do the same it will all tie in. prove it to yourself and follow a phase threw all the tx's, do the same will b & c phases. I do it all the time at my job, works every time.

You can't characterize a circuit type in this way. In a digital circuit a ribbon cable with parallel wires usually indicates a parallel connection as opposed to a serial connection or interface.

They all have a rotating commutator in the centre and a coil surrounding it.

A DC drive is a kind of equipment ordinarily do control a speed, tension and current on a Direct Current Motor (DC Motor), in order to have a certain process transformation under control.

A short circuit. In a properly installed system the fuse will blow to prevent a fire.

I first asked the question. I was told by an electrical engineer that the appliances would breakdown after between 1 day and 2 weeks use and he advised me to sell and buy new appliances in the Philippines. I was not able to obtain a reasonable price for selling second hand appliances and also found that appliances in the Philippines were very expensive compared to Malaysia. I was also told in the Philippines that the appliances would work satisfactorily . So I installed all the appliances and after 3 months they work OK except the clock which gains about 3 hours per day.My appliances include 2 refridgerators. 2 wine coolers, freezer.4 TV's,washing machine ,dryer,dishwasher,computer,fax ,etc. David dlw@tm.net.my

Of course, but it will change all parameters (HP, torque etc.) The problem is someone would have to redesign of that motor, size of coils in field winding according to new voltage, speed and HP ratings. Basically, is not worth it.

In the US, I would recommend MIT, Carnegie Mellon, California Poly Tech (CalTech), Rochester Institute of Technology, although its ALL WHAT YOU MAKE OF IT, and how much effort you put into your studies. A degree from an accredited State University will give you a lot of Bang for Your Buck.

to protect a circuit from damaging

All those three, and outdoors as well. Electricity is used everywhere and for many different things, so electrical engineers have to be where the electricity is, to make sure it's used safely and correctly.

The part that rotates inside of an electric motor is called the rotor.

A: It realy does not matter half or full wave. the PIV will be 1.41 the RMS input example 100v ac will have a requirement of PIV of 141 volts on the rectifiers.

the currents move back and forth ( alternating current) when something is plugged into a socket, the ac voltage (120 v) is moved to the device.

then there is dc voltage, dc voltage works with electricity flowing straight to a device, it does not alternate. just as a battery hooked up to a wire, connected to a switch, connected to a light, connected to the battery again.

ac could connect to the light from the switch , from the battery.

The load current in an electrical system isn't determined solely by the power factor. The power factor, which can range from -1 to +1, is a measure of how effectively the electrical power is being converted into useful work output. A power factor of 1 (or 100%) signifies that the power is being used entirely effectively, with no reactive power.

However, to determine the load current, you would also need to know the power (in watts) and the voltage (in volts) being used in the system. The formula to calculate current (I) is: I = Power (P) / Voltage (V). So, if you have a power factor of 1, it means that all the power is being used effectively, but it doesn't directly determine the load current.