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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 much Ampere when volt 415?
That would depend on the power output (watts) of the circuit.
Volts times the Amperage equals the Wattage of the circuit. You do not have enough information in your question. Volts is the force applied to move the electrons in the circuit, and amps are a measure of the quantity of electrons moved through the circuit over time. Thus a circuit of 415 volts and 1 ampere will deliver 415 watt-hours of power. Yet a circuit of 1 volt at 415 amps will deliver the same 415 watt-hours of power, but with less force.
How do you calculate current consumption per hour?
You are confusing energy and current. You consume, and pay for, energy -not current.
For the purpose of billing its customers, an electricity utility measures energy in units called kilowatt hours. In the UK, a kilowatt hour is also called a 'unit', short for 'Board of Trade unit'. The Board of Trade, which no longer exists, used to be the government organisation responsible for setting energy prices.
A unit, or kilowatt hour, of energy is the amount of energy consumed at the rate of one kilowatt over a period of one hour. So, to determine the number of units that an electrical load 'consumes', you simply multiply its power in kilowatts by the time for which it operates, in hours.
When lines of force are cut by what you have electromagnetic induction?
When magnetic flux lines of force are cut by induced voltage between magnetic and electric currents. Electromagnetic induction is created.
Let us look at a black box with two external terminals and the black box is composed of only passive elements.
Conservation of charge means that what goes in one terminal has to exit the other terminal, or else electrical charge will accumulate or deplete inside the black box.
Current is just charge per unit time. Current going in one terminal has to exit without loss the other terminal.
Resistors are passive element. In this situation, we have two black boxes, each is composed of one resistor. What goes in = what comes out --> the current is the same in both resistors.
What device do you use to determine how much resistance is in a circuit?
There are many different devices, depending on what you need to measure.
The most common are a multimeter or an oscilloscope. But there are thousands of other devices some costing less than a dollar and can be held in the palm of your hand up to others costing hundreds of thousands of dollars that are installed in an 8 foot tall standard 19 inch wide relay rack.
What is the voltage source and what is the conductor in a circuit?
The voltage source is the source of the electricity.
The conductor is what the electricity flows through to reach its destination.
Example: A battery is a voltage source and an electrical wire is the conductor.
Can you connect two air conditioner on single phase power supply?
US NEC:
You can connect two air conditioners on a single phase power supply, but...
The correct question is probably, "Can you connect two air conditioners to a single distribution circuit?". The answer is no - any substantial load requires its own distribution circuit.
Differences of induction motors and synchronous motors?
An induction motor is a type of electric motor. It uses alternating current (AC) electricity and induces (hence the name) a current in the rotating part to make it move. You might call it a rotating transformer. A hydraulic motor is powered by a fluid. Typically this might be an oil, The oil forces round some gears or vanes to make the motor shaft turn. A hydraulic motor requires an external supply of pressurised fluid, e.g. oil. Large earthmoving equipment or diggers use hydraulic power as it is compact and powerful for its size.
How do you minimize core losses?
Hysteresis and eddy current loss constitute core loss. It can be reduced by replacing solid core by laminated core... by adeeb
What are causes of voltage drop?
Think of it in terms of a central heating system that uses a number of radiators: the water pump applies pressure across all the radiators. But there must also be a pressure difference across the inlet and outlet to each radiator, or water wouldn't flow through the individual radiators. The sum of these pressure differences will equal the pressure delivered across the entire system by the pump.
Now imagine a number of resistances connected in series. There must be individual potential differences across each resistance or current wouldn't flow through them. We call these individual potential differences, 'voltage drops', and the sum of the voltage drops across each resistance will equal the magnitude of supply voltage, but act in the opposite sense.
The flow of negative charges through matter is called?
A continuous flow of negative charges is called an electric current.
How do you know the voltage drop of wire?
Voltage = Current x Resistance. To calculate the voltage drop of a piece of wire, you would have to know the current flowing in the circuit and the resistance of the wire. The resistance of wire depends on the material it is made of, the length, and the cross sectional area (also called gauge or AWG). Short thick wires have less resistance than long thin wires. You can look up the resistance of the wire on the Internet, and you can measure the current flowing by connecting an ammeter in series with the circuit. Multiply those two numbers and you will have closely approximated the voltage drop across the wire.
Very. Every foot of trackage must be a linear motor. That takes a lot of copper.
Which is not cheap.
And don't forget the power requirements ... holding up a whole train is not cheap.
What is difference between power station generator and dynamo generator?
- Generating Capacity : Power plant has very high generating capacity as compared to gen set.
- Size of the equipment : Size of the alternators are compatibly very big in Power plants.
- Type of Prim-over : In Power plant turbine is used to for prime over or to provide mechanical power to rotor of the alternator whereas in generating set diesel engine is used for prim-over.
What is excitation of DC machine?
In general terms, 'excitation' simply describes the process by which an electric current produces a magnetic field. But, more specifically, it refers to the creation of the magnetic field by the field windings of a motor or generator.
In the case of an alternator, for example, the armature windings (the windings into which voltages are induced) are stationary, and inserted into slots cut into the inner face of the stator. The field is then provided by the rotor which is supplied (via slip rings) with a 'excitation' current provided by an external d.c. voltage.
How do you change the direction of rotation on a three phase motor?
Very Simple Inter change any one phase, in three phase suppose u connected R.Y.B phase to U.V.W In motor terminal, change it to R.Y.B to V.U.W
AnswerAll that is necessary is to interchange any pair of line conductors.
Why you need to measure insulation resistance?
It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it.On the whole megger testing is non destructive. What happens is a DC voltage is applied to the device or winding under test. On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing. Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range. As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.
Working of single phase energy meter?
An electric meter or energy meter is a device that measures the amount of electrical energy supplied to or produced by a residence, business or machine.
The most common type is a kilowatt hour meter. When used in electricity retailing, the utilities record the values measured by these meters to generate an invoice for the electricity. They may also record other variables including the time when the electricity was used.
Modern electricity meters operate by continuously measuring the instantaneous voltage (volts) and current (amperes) and finding the product of these to give instantaneous electrical power (watts) which is then integrated against time to give energy used (joules, kilowatt-hours etc). The meters fall into two basic categories, electromechanical and electronic.
Electromechanical metersThe most common type of electricity meter is the Thomson or electromechanical induction watt-hour meter, invented by Elihu Thomson in 1888.[1][2]TechnologyThe electromechanical induction meter operates by counting the revolutions of an aluminum disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage. It consumes a small amount of power, typically around 2 watts.
The metallic disc is acted upon by two coils. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees using a lag coil. [1]This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and voltage. A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc - this acts as a brake which causes the disc to stop spinning when power stops being drawn rather than allowing it to spin faster and faster. This causes the disc to rotate at a speed proportional to the power being used.
The type of meter described above is used on a single-phase AC supply. Different phase configurations use additional voltage and current coils.Reading
The aluminum disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of energy used. The dials may be of the cyclometer type, an odometer-like display that is easy to read where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. It should be noted that with the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism.
The amount of energy represented by one revolution of the disc is denoted by the symbol Kh which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the value of Kh, one can determine their power consumption at any given time by timing the disc with a stopwatch. If the time in seconds taken by the disc to complete one revolution is t, then the power in watts is . For example, if Kh = 7.2, as above, and one revolution took place in 14.4 seconds, the power is 1800 watts. This method can be used to determine the power consumption of household devices by switching them on one by one.
Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter.Accuracy
In an induction type meter, creep is a phenomenon that can adversely affect accuracy, that occurs when the meter disc rotates continuously with potential applied and the load terminals open circuited. A test for error due to creep is called a creep test.
How is the minimum fusing current related to the current rating of a fuse?
Each fuse has its own rating. It will be marked on the fuse somewhere.
What is the formula for calculating wattage?
wattmeter is constructed such that it read only power on a single scale. Only single scale will avilable to read the measured power. In order to take the acuurate reading just we measure the reading and we will multiple along with factor called multificaion factor. That's depends on on which voltage knob we connected and also the current.
Multification factor can be dtermind by:
Multification factor =(voltage range*current range*pf)/Max scale deflection...
What is resistivity and conductivity and the relation between them?
There are two expressions of the relationship between power and resistance. They are P = I2 x R (power equals current squared times resistance) and P = E2 / R (power equals voltage squared divided by resistance).
What is the starting method of synchronous motor?
There are 5 types of starting in induction motors:
1) resistance variable method
2) auto transformer method
3) slip ring induction motor method
Squirrel cage induction motor using two types of starting methods
1.Direct on line starter
2.Star delta starter
In a circuit the electrons flow from what side to what side?
Conventional electrons flow is understood to be flowing from a positive force a less positive force.
How many lumens in 40 watt fluorescent tube bulb?
There is no fixed relationship between the brightness (lumens / candela) of a light source, and its power consumption (watts). Incandescent bulbs have a low luminous output for their power consumption, Compact Fluorescent Lamps are intermediate, and LED's are the most efficient in today's world.
How do you calculate back up time of battery?
battery backup is fully depended on battery discharge characteristics.
discharge characteristics are c1 c5 c20
Need to consider c factor, calculating backup of batteries
100 AH BATTERY DISCHARGED BY 5 AMP CONSTANT = 100 AH
100 AH BATTERY DISCHARGED BY 20 AMP CONSTANT= 85 AH
100 AH BATTERY DISCHARGED BY 50 AMP CONSTANT=70AH
100 AH BATTERY DISCHARGED BY 100 AMP CONSTANT=50AH
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Battery back up time=Battery current at full load/Battery Ah
