You know the KW and KWh, VA and W is what meaning, is there a difference?

What the difference between the kW and kWh? KW is the unit of electric power, kWh is the unit of electrical energy. How many quantities kWh electricity is according to current work. The international standard unit of energy is the joule ( J） , but in the power system is commonly used in kWh, MWh, said 1 MWh = 103 kWh = 3. 6*109J。 Is 1 KWH for 1 kw of power equipment to produce in 1 hour or consumption of electricity. Power plant capacity of the actual operation of the product of power and operation hours, we commonly used in speaking of electricity consumption & other; C & throughout; This unit, 1 = 1 KWH. Second, kW power said current work speed, the speed of the produce or consume electricity, unit for watt ( W) 。 We often use the unit kW, MW, GW is equal to 103, 106, 109 watt, respectively. Power is the rate at which it produces electricity generators, the system capacity is the sum of rated active power generating sets of actual installation. In electricity, electrical household appliances refers to the rate at which it consumes electric power, such as the 45 w bulb is greater than 15 w lamp power, brightness is more bright. The relationship and difference between the two units are used to characterize electrical energy production and consumption process, kW representation of the process speed, however, kWh represent the total energy of the process. Their relationship like speed and distance, can be used to describe a journey, but with different emphasis. Calculation formula is: electrical power = * time, such as power is 1 kw electrical work 5 h, the power consumption for 1 kw * 5 h = 5 KWH. What's the relationship between VA and W. First explain the VA, W and Var is not power, they are just power unit, the apparent power ( With a S) , the active power ( With P said) And reactive power ( In the Q) Of the unit. What is the relationship between them, we see their formula: apparent power S = UI active power P = UIcosΦ Reactive power Q = UIsinΦ The phase difference between voltage and current ( Φ ) Cosine is called power factor, use symbol cosΦ Said. According to the formula can be seen that the relationship between them is that S ^ 2 = P ^ 2 + Q ^ 2 in ac circuits, the power supply load of power has two kinds: one kind is active power, is a kind of reactive power. 一个。 Active power is needed to keep the normal operation of electrical equipment of electric power, is that converts electrical energy into other forms of energy ( For example, mechanical energy, light energy and heat energy) The electric power. b。 Reactive power are abstract, it is used for circuit inside the exchange of electric and magnetic fields, and used in electrical equipment set up and maintain the magnetic field of electric power. Not foreign work, it is converted into other forms of energy. All electrical equipment of electromagnetic coil, to build a magnetic field, will consume reactive power. Reactive power is by no means useless power, it is of great use. Motor need to establish and maintain a rotating magnetic field, make the rotor rotation, so as to drive the mechanical movement, motor rotor magnetic field is obtained from the power supply reactive power. Also need to reactive power transformer, to make a magnetic field coil, transformer in the secondary coil induction voltage. Therefore, without reactive power motor won't turn, nor transformer transformer.