# The motor power VA and W what is the point?

by：J&T     2020-06-30
Has been widely used in chemical production, motor, power of VA and W is what meaning, what is the relationship? 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. Remember is active reactive power, not useful useless! ! ! 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 we can put the success rate of three kinds of power to draw a triangle, two sides respectively, active power and reactive power, apparent power hypotenuse. Add: in ac circuits, the power supply load of power has two kinds: one kind is active power, is a kind of reactive power. 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. 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.
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