Driven by converter with high energy space, many countries have designated flow pressure must be controlled by using frequency conversion speed regulation device replaces the traditional way, China National Energy Act twenty-ninth section second also stipulate the fan and pump load should be used in power electronic control.
1, variable frequency energy saving
A fluid mechanics, P ( power ) =Q ( flow ) H ( pressure ), flow rate Q and the speed is proportional to N a H N, pressure and rotational speed is proportional to the square of the speed, power of P and N is proportional to the cube of the efficiency of pump, if certain, when asked to regulate the flow down, the rotating speed of N is proportional to the drop, and the power output shaft P cubic relationships decline. The pump motor power and speed than the approximate relationship establishment. For example: a pump motor power is 55KW, when the speed drops to the rotational speed of the 4/5, its power consumption is 28.16KW, power 48.8%, when the speed drops to the rotational speed of the 1/2, its power consumption is 87.5% 6.875KW, power saving.
2, power factor compensation energy saving
Reactive power will not only increase the loss and equipment for heating, more important is the power factor resulted in lower system power is reduced, a large number of reactive electric energy consumption in line, equipment use efficiency is low, wasteful and serious, the formula P=S COS ФQ=S, SINФS-, wherein the apparent power, P- the active power, reactive power, Q-, COS Φ- power factor, the COSФlarger, active power of P is higher, general pump motor power factor in between 0.6-0.7, the use of variable frequency speed regulation device, because the frequency converter internal wave filtering capacitance effect, COSФ≈ 1, thereby reducing the reactive loss, increased power system reactive power.
3, soft start energy saving
Because the motor is started directly or Y/D start, the starting current is equal to ( 4-7 ) times the rated current, so will the mechanical and electrical equipment and power supply network caused severe impact, but also to power grid capacity requirement is exorbitant, from starting of large current and vibration on baffle and valve damage to equipment, greatly, the service life of the pipeline extremely bad. While the use of frequency conversion energy-saving device, the use of frequency converter soft start function will make the starting current and start from zero, the maximum value is less than the rated current, reduces the shock on the power grid and the power supply capacity requirements, extended equipment and the service life of the valve. Save maintenance cost of the device.
