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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
How can you terminate a 3 wire wye motor to a 3 phase delta connection?
To terminate a 3 wire wye motor to a 3 phase delta connection you need a 3 phase transformer to convert from delta to wye. Do not lift the common neutral connections inside the motor and rewire for delta, because the voltages will be wrong.
Why an electrical device will not work if the neutral is not connected in a single phase system?
To make any electrical circuit work it has to be complete. Source of power to the load, the load itself and a return path from the load back to the source. The source in this case being the distribution panel. Any breaks in this complete path will cause the current to stop flowing and the device to not work. A light fixture and light switch work on this principle, open the circuit and the light goes out.
What will happen if apply two phase supply to a three phase transformer?
A three phase transformer is simply three transformers so, supplying one phase to a set of three transformers will result in only one phase output. Any loads connected to that transformer that are expecting three phase power will malfunction, and could fail.
Answer
A three-phase transformer is NOT 'three separate single-phase transformers', as suggested in the original answer. It is a single transformer with three primary and secondary phase-windings wound around a common three-limb ('core') or five-limb ('shell') core. If a single-phase supply was applied to one of the three primary windings, then single phase voltages would appear across each of the three secondary windings and the remaining two primary windings. These voltages would not be out of phase with each other.
What would full load amps be on a 480volt 90 kw electric heater be pulling 36 amps per leg?
90 kW on 480 volts single phase would be 187.5 amps. On 480 v 3-phase it would be 108 amps.
What color is single phase electrical supply?
In the US system, the hot phase is designated by a color other than white, except that bare or green is non-current carrying, or safety, ground. In a 120/240 split phase system, the most common home system, hot is black in a 120 volt circuit, and the two hots are black and red in a 240 volt circuit. Also, switched hot in a 120 volt circuit is red, but it does not really matter as the rule is "white is neutral" and "non-white is hot".
Can someone add to this, please, for the UK and other systems.
Answer'Phases' are not identified in three-phase systems. Colours, letters, or numerals are used to identify lines.The UK's and other EU countries' nominal single-phase supply voltage is 230 V at 50 Hz. The conductors are identfied as follows in line with EU standards:
- line (not 'phase') conductor brown
- neutral conductor blue
- protective conductor green/yellow stripe
For three-phase (400/230 V) systems, the line conductors are coloured brown, black, and grey.
Prior to the EU harmonisation requirements, the UK's single-phase conductors were coloured as follows, and these will be found in all installations that pre-date the EU requirements:
- line conductor red
- neutral conductor black
- protective conductor green
For three-phase systems, the line conductors were coloured red, yellow, and blue.
Which component is used to measure the current in a circuit?
an ampmeter.
Most DVM's have them, or you can use a clamp on style.
What is meant by RLC circuits in series?
It means that you have the following three elements in series: R (resistance), L (inductance), C (capacitance).
It means that you have the following three elements in series: R (resistance), L (inductance), C (capacitance).
It means that you have the following three elements in series: R (resistance), L (inductance), C (capacitance).
It means that you have the following three elements in series: R (resistance), L (inductance), C (capacitance).
What is the purpose of 'Open Circuit Test' in Electrical Power Engineering?
Open circuit test shows total voltage of a source such as a battery, transformer, energized circuit. Often, solar panels list open circuit values. The purpose is to prove that the design or nominal voltage is present. For solar panels open circuit voltage proves that the individual cells are connected and connected correctly. Open circuit values can be the standard to quality check two or more sources or circuits that have equal factory standards. Other uses: generators compare open circuit voltage exciter winding to actual useable output voltage winding for the purpose of correcting output with a signal to voltage regulator-Voc is an ideal reference; open ckt test can be used to test wire insulation for holes or damage because Voc can be made to go so high it will force an arc through damaged insulation; Voc tests are used to locate voltage or detect intact wiring or severed wires. Many more uses in electronic devices like high z input to digital tristate gates. High Z is open input, which is stable "on", applied voltage is timed pulse train, and ground is active "off"
The one thing to remember, open circuit tests always mean no current, no heat, no wear, no battery drain, but never believe no shock hazard. Voc will shock and can arc and start fires.
Is a voltage and current source the same thing?
Voltage source inverters use the dc voltage (e.g a capacitor in parallel) as a source while the current source inverer (inductor in series) use the dc current as a source. Please note that voltage can not be changed abruptly in capacitor as current can not be changed abruptly in inductor.
Lugs for higher current applications are called barrel lugs. These types have to be crimped on to the wire using a hydraulic crimper. A smaller type of lug is a block lug that used Allen Keys to tighten it to a conductor. The smallest type of lug used mostly for grounding junction boxes and control panels uses a screwdriver for tightening the lug to the conductor.
What are disadvantages of harmonics?
harmonics increase heating of motors ,transformers and capacitors .Power system protecting relays may operate falsly, meters give inaccurate readings,interference with telephone lines may also occur.
Moreover resonance due to harmonics also causes problems
How do you convert watts into amperes?
To convert watts into amperes you divide the circuit voltage into the watts. Amps = Watts/Volts.
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Converting Watts to Amps
The conversion of Watts to Amps is governed by the equation Amps = Watts/Volts
For example 12 watts/12 volts = 1 amp
Converting Amps to Watts
The conversion of Amps to Watts is governed by the equation Watts = Amps x Volts
For example 1 amp * 110 volts = 110 watts
Converting Watts to Volts
The conversion of Watts to Volts is governed by the equation Volts = Watts/Amps
For example 100 watts/10 amps = 10 volts
Converting Volts to Watts
The conversion of Volts to Watts is governed by the equation Watts = Amps x Volts
For example 1.5 amps * 12 volts = 18 watts
Converting Volts to Amps at fixed wattage
The conversion of Volts to Amps is governed by the equations Amps = Watts/Volts
For example 120 watts/110 volts = 1.09 amps
Converting Amps to Volts at fixed wattage
The conversion of Amps to Volts is governed by the equation Volts = Watts/Amps
For Example, 48 watts / 12 Amps = 4 Volts
Explanation
Amps are how many electrons flow past a certain point per second. Volts is a measure of how much force that each electron is under. Think of water in a hose. A gallon a minute (think amps) just dribbles out if it is under low pressure (think low voltage). But if you restrict the end of the hose, letting the pressure build up, the water can have more power (like watts), even though it is still only one gallon a minute. In fact the power can grow enormous as the pressure builds, to the point that a water knife can cut a sheet of glass. In the same manner as the voltage is increased a small amount of current can turn into a lot of watts.
What subjects do i need to choose for grade 10 for electrical engineering?
well. the main subject is maths in it then physics
AnswerWould you believe it's 'electrical engineering'?
How many wires used for 3 phase?
There is no voltage in three phase wire. The ability of wire to carry voltage is dependant upon the insulation that surrounds the wire. The thicker the insulation the higher the voltage potential can become. Three standard insulation voltages are 300, 600 and 1000 volts.
Another Answer
First of all, there is no such thing as a voltage 'on' a wire. 'Voltage' is another word for 'potential difference', so a voltage can only exist between two wires. Voltages in three-phase systems are generally specified in terms of their line voltages-i.e. the voltage between any two line conductors. These depend on the electrical standards used in the country in which you live. In the UK, for example, three-phase transmission lines will have line voltages of 400 kV, 275 kV, or 132 kV, while distribution lines will have line voltages of 33 kV and 11 kV, and low-voltage distribution line voltage is 400 V.
Does rhodium conduct electricity?
Yes, rhodium is a good conductor of electricity. It is commonly used in electrical contacts and as an alloy in electrical components due to its high electrical conductivity and resistance to corrosion.
What is the purpose of the use of the electrical isolator?
It is a transformer used to exchange electrical force from a wellspring of substituting current energy to some gear or gadget while secluding the fueled gadget from the force source, more often than not for wellbeing reasons. Disengagement transformers give galvanic confinement and are utilized to secure against electric stun, to smother electrical commotion in delicate gadgets, or to exchange force between two circuits which should not be joined. It sold for disconnection is frequently assembled with exceptional protection in the middle of essential and optional, and is indicated to withstand a high voltage between windings.
How torque is produced in a induction motor?
Torque is a Force applied at a Moment Arm. Or a force applied to a bar of a set length. Torque is a unit of Foot-pounds. If you have a ratchet wrench that has a 1 foot handle and you use it to torque a Bolt by applying a force of 20 lbs this will produce a 20 ft-lb torque load to the bolt. ( 1 Foot X 20 Lbs). This can be converted to 240 inch-lbs. The torque produced by car engines are also measured in terms of foot-pound of torque. This defines the power that the engine produces at the Shaft. This is convenient to use in calculating how much power is delivered to a car's transmission or wheels to allow the engineer to determine how fast the car will go, etc.
How do you reduce 60volts ac to 12volts ac?
A number of ways. Assuming a typical DC power supply you could: 1) Increase the turns ratio (n) on the transformer. 120 to 24 is roughly 5:1 ratio. Making that a 10:1 ratio would provide 12V. #2 below would be required as well. 2) Change the voltage regulator. Whether it be a zener diode, or LM78xx regulator, it could be changed to provide 12V. 3) A voltage divider set of resistors. Using two equal-valued resistors, you could divide the voltage in half. A potentiometer at 50% accomplishes the same thing. Both options 2 and 3 alone reduce the voltage by dissipating the excess energy as heat, so they are the least efficient choice.
How can you calculate busbar size?
Busbar Length x Busbar Size x 0.009
ex- Length= 12meter
Size = 60 X 10 mm
ie, 12 x 60 x 10 x 0.009
Ans = 65 kg
Can you please let us know what is "0.009" for???
Ans: 0.009 = copper density
Max. Current for 60 x 10mm = 60 x 10 x 1.55 = 930 AMP
What is "1.55" for??
How can you convert single phase transformer into three phase transformer?
In order to convert from single phase to three phase, you need an inverter or some kind of motor-generator.
Variable Frequency Drives for electric motor speed control now feature single phase input with three phase output for motor loads up to 3HP. Good for the home shop where you got a deal on some equipment but lack 3 phase power. For instance, Google this: ATV12H075F1
Why is calculated current different from measured current in a circuit?
No component is perfect. All have tolerances that can vary. If you construct a simple circuit where a 10 volt power supply feeds a 10 ohm resistor, you would expect to measure a current of one ampere. BUT - the wiring has some resistance too. This adds perhaps 0.1 ohms to the circuit. The resistor has a +-5% tolerance. If it is 5% high, it may measure 10.5 ohms. That's a total circuit resistance of 10.6 ohms. The power supply may have a tolerance of +-1%. Suppose it's 1% low. That's an output of 9.9 volts in real life. So you have 9.9 volts dropped across 10.6 ohms. you will measure closer to 0.934 amps instead of 1.000 amps. To make matters worse, most electronic components have a temperature coefficient, that is, their values change with different temperatures. You may get a completely different reading tomorrow if the temperature is different! Finally, with current measurements in particular, you are inserting the ammeter in series with the circuit under test. Ammeters have some inherent resistance too, so by putting the ammeter in the circuit, you are changing the very current you are trying to measure (a little)! Oh yeah, the ammeter has a tolerance too. Its reading may be off a little even if everything else is perfect. Sometimes you have to wonder how we get a decent reading at all. Fortunately the errors are usually fairly small, and not all tolerances are off in the same direction or off the maximum amount. They tend to cancel each other out somewhat. BUT - in rare circumstances everything CAN happen like I said, and the error can be huge.
How do you get 480v 3 phase from 220v single phase?
Buy either a phase convertor or motor-generator with the proper input and output ratings. Essentially you have to generate your own 3-phase power using the 220V as the energy input. There is no wiring or connection scheme that will directly do this.
Is there any difference between voltage and potential?
Voltage . . .
The 'pressure' between two points that makes electrons 'want' to move from one of the points to the other one. More pressure is called more 'volts'. This can determine the brightness of lights and the speed of electric motors.
Current . . .
the flow of electrons between those two points, IFthere's something in the space that the electrons are able to flow through. More current is called more Amperes (or 'amps').
The amount of current depends on how strong the voltage is, AND on what the electrons are flowing through in order to get across the space. (That's called the 'resistance' between the two points. Resistance is measured in 'ohms'. More ohms means it's harder for the electrons to get across the space, and the result of that is ... less current.)
Comment:
It's also worth pointing out that current is only a flow of electrons in (mainly) metal conductors. In other conductors, such as electrolytes, a current is a flow of ions (charged atoms) rather than electrons -sometimes different types of ions flowing in opposite directions to each other at the same time. A more general definition of current, therefore, would be 'a flow of charge carriers'.
Would you connect a voltmeter in series or parallel with bulb to measure voltage across it?
To measure the voltage across a bulb, you would connect a voltmeter in parallel with the bulb. This configuration allows the voltmeter to measure the potential difference across the bulb without significantly altering the circuit's operation. Connecting it in series would prevent the proper function of the circuit and could potentially damage the voltmeter.
