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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
230V line to line a single phase?
Yes. 230V line to line is considered single phase power. The 115v half part of that is called split phase. It should not be called two phase, as it is one phase that has been center tapped and grounded at the neutral point - it is still one phase power.
Answer230 V is the standard nominal voltage for residences in Europe. 230 V is the line-to-neutral voltage (phase voltage). Low-voltage distribution is by three-phase, four-wire, system with a nominal line voltage of 400 V and a nominal phase voltage of 230 V.
Why there is a need of interconnection in electrical power systems?
We need these interconnections because apart from delivery, the purpose of the transmission network is to pool power plants and load centers in order to minimize the total power generation capacity and fuel cost. Transmission interconnections enable taking advantage of diversity of loads , availability of sources and fuel price in order to supply electricity to the loads at minimum cost with a required reliability.
What is the typical voltage of a control transformer for a three phase 480 volt starter?
Most 3 Phase 480V Starters are controlled by 120VAC. This is because the coils on the contactors (starters) are 120VAC. Just ensure the voltage matches the coil.
What is the affect of a series circuit on current?
by adding the the resistances in series the total resistance of the circuit increses and thus the crunt flowing in the circuit decrese.
Ans 2 .
the current in series circuit of constant resistance will always be the same . It will not effect the current .
What are the protective devices incorporated in DC starters?
The No volt coil (NVC) and the Overloadrelease(OLR) are the two protecting devices incorporated in DC starters
What appliances would have a 3amp fuse?
Depending on your voltage supply appliances of between 500 - 750 watts
What is the role of bath impregnating in electrical trade?
bath impregnating is used to varnishing of motor or generator in electrical trade.
Why is electrical resistivity important to a design engineer?
electrical resistance increases current flow decreases.so to know the current flow in the network ,electrical resistance is required.
AnswerResistivity is important, because it is one of the three factors that affect the resistance of a material. The other factors are the length and cross-sectional area of the material.
How do you connect a 230V lamp to a 415V supply with no neutral?
Theoretically, you could connect three identical lamps in star (wye) and connect this to the three line conductors. But as you asked how to connect a (single) 230-V lamp to the supply, then the answer is by using a step-down transformer.
There are two sections of the fuse; a straight wire section that provides quick acting response to short circuit conditions, and a coiled spring section with a soldered lump with thermal mass that provides time delay for normal overload. When inspecting a blown fuse, you can tell if it was a short or an overload by looking at where the blowout occurred.
What is the function of polarized capacitor?
Polar capacitor used in those places where the voltage will never switch polarity on them under proper use conditions. Their high capacitance means they can be used more effectively for power supply filtering, reducing ripple in a rectifier, and softening on/off switching.
Why don't they just use 440 vac capacitors for all condensers and get rid of 370 vac capacitors?
Because when a fan motor (or compressor), is designed to operate on a 370 VAC run capacitor, that will be its optimal efficiency operating design. We're talking about capacitors used on an A/C in a typical 230 volt power supply to a residence or business. If you substitute a 440 VAC run cap in place of the 370 cap, the motor will seem to operate just fine. However, if you put an amprobe on the motor, you will find an increase in the amps it is drawing. This translates to increased heat in the windings, and some motors can handle a small heat rise while others have a problem with it. It partly depends on the airflow over the fan motor along with the quality of the motor, but in any event, you are decreasing the life of the motor along with paying for the electrical current you're wasting, and also, not using the specified cap the motor calls for, in most cases, will void the motor's warranty. The worst place to substitute a 370 VAC cap with a 440 VAC cap is on a compressor. The increased heat load in the windings causes an increase in head pressure and on some compressors already operating at high head pressure and heat load, the compressor can trip off and will stay off until the shell cools down. Of course, the additional amp draw in the compressor will really drive up the power bill. Bottom line, use the cap the motor specs call for. If you have to substitute to get-by because you don't have the right one on your truck, go back the next day and put the right one in. George Henne--Retired A/C Tech----
What is the voltage regulation of an ideal transformer?
Ideally the voltage regulation voltage of a transformer should be zero. It means when you change the load from no load to short circuit (theoretically, normally you don't want to burn the transformer windings) the output voltage doesn't change and remains equal to the no load voltage.
How do you test reverse power trip?
There is a test swich which will change the polarity of the sensors........
What happen to lamp if over voltage?
A lamp will only operate at its rated power if it is subjected to its rated voltage. Increase that voltage will increase the power of the lamp -in other words, it will operate more brightly. This is how 'photoflood' lamps operate -they are deliberately designed to operate at overvoltage. Of course, this reduces the life of the lamp.
What is the power when there is 500 mA of current through 4.7 Kilo ohm's of resistance?
Ohm's Law: Voltage is current times resistance, so 0.5 A through 4700 Ohms is 2350 volts. Power Law: Power is voltage times current, so 2350 volts times 0.5 A is 1175 watts.
WARNING: This is both high voltage and high power. Do not attempt to duplicate this in the lab without adequate protection and appropriate components.
