Power=Volts x Amps Unit for power is watts
Volts time amperes is watts.
Volts is joules per coulomb. Amperes is coulombs per second. When you multiply the two, you get joules per second, which is also known as watts.
power
An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name
VA or, more correctly, V.A, is the symbol for volt amperes, which is the unit of measurement for the apparent power of an alternating-current load.In A.C. circuits, true power (measured in watts) is a measure of the rate at which energy is supplied to the load, and reactive power (measured in reactive volt amperes) is a measure of the rate at which energy is alternately stored in the circuit's magnetic field and returned to the supply. Apparent power is the name given to the vector sum of true power and reactive power.
The speed of motion generated by a motor is not a function of its nominal power. The nominal power, 3kW in this example, is an indicator for the electric power consumed, and for the force available in the direction of motion. The speed of a motor is determined by its construction, and can cover an extremely wide range regardless of its power.
Electrical power = current x voltage Current is in amps
Actually, electric utilities object to a lagging power factor, but it does not really matter if its leading (capacitive) or lagging (inductive). The problem is that true vs apparent is less than unity - that's the definition of power factor - and this causes the indicated power (KW) to be less than the actual power (KVA) by a trigonometric relationship between KW and KVAR (kilo volt-amperes reactive). That energy is still required to be provided, and this requires facilities in excess of what is indicated by the power meter.
If you refer to the units, power (any power, not just electrical power) is energy divided by time. The SI unit is the watt, equal to 1 joule/second.
An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name
KVa is not the same as the amperes because KVa is the unit for reactive power while amperes is the unit for current.
If you are talking about a capacitor bank used for power-factor improvement, then it is rated in reactive volt amperes (var). Otherwise, it is rated in farads (F).
Capacitors designed to be used for power-factor correction are rated in reactive volt amperes, rather than in farads.The reason for this is that in order to determine the necessary correction, a load's existing reactive volt amperes is first calculated, then the reactive volt amperes of the capacitor must be determined in order to achieve the required value of power factor. In other words, the capacitance (in farads) of the capacitor is irrelevant to the calculation.
The relation is:P = I2RWhere:I is the current (for example, in amperes)R is the resistance (for example, in ohms)P is the power (energy per second) converted from electrical energy to heat. If the current is in amperes and the resistance in ohms, then power is in watts (equal to joules/second).
There is no "unit of electricity" metric or otherwise. There are units of measurement for electric charge (coulombs), potential (volts), current (amperes), energy (joules) and power (watts).
'Reactive power' is the rate at which energy is stored in an electric or magnetic field, and returned to the supply. To differentiate between reactive power and true power (the rate of heat transfer and of work), and for no other reason, it is expressed in reactive volt amperes (var) rather than in watts (W). Its significance is that it is necessary to establish and sustain electric and magnetic fields.
Transformers are rated in KVA. (this is because the transformer is Unity power factor device i.e.. PF = 1)AnswerThe selection of a transformer is determined by the apparent power of the load, expressed in volt amperes(V.A), the load current, and the line voltage of the supply. The transformer must be able to satisfy these requirements.Transformers are not 'unity power factor' devices, which is precisely why their capacity is expressed in volt amperes, rather than in watts.
'Reactive Power', which is expressed in reactive volt amperes, describes the rate at which energy is alternately stored (in a circuit's electric or magnetic field) and returned to the a.c. supply when the field collapses. It differs from true power, expressed in watts, because true power describes the rate at which energy is permanently lost by heat transfer due to the resistive component of the circuit.Reactive power doesn't 'have an use', per se, it's merely a way of quantifying the movement of energy in the reactive component of an a.c. circuit.The vector sum of a circuit's reactive power and its true power is called the apparent power of the circuit, expressed in volt amperes.
VA or, more correctly, V.A, is the symbol for volt amperes, which is the unit of measurement for the apparent power of an alternating-current load.In A.C. circuits, true power (measured in watts) is a measure of the rate at which energy is supplied to the load, and reactive power (measured in reactive volt amperes) is a measure of the rate at which energy is alternately stored in the circuit's magnetic field and returned to the supply. Apparent power is the name given to the vector sum of true power and reactive power.
The speed of motion generated by a motor is not a function of its nominal power. The nominal power, 3kW in this example, is an indicator for the electric power consumed, and for the force available in the direction of motion. The speed of a motor is determined by its construction, and can cover an extremely wide range regardless of its power.