The function of frequency converter is mainly to adjust the power of the motor, realize the variable speed operation of the motor, in order to achieve the purpose of power saving. At the same time, the role of frequency converter can reduce the power line voltage fluctuations, because the voltage drop will lead to the same power supply network voltage-sensitive equipment failure tripping or work abnormally. After adopting the frequency converter, the role of the frequency converter can start gradually at zero frequency and zero voltage, which can maximize the elimination of voltage drop and play a greater advantage.
Frequency conversion energy saving
Frequency converter energy saving is mainly manifested in the application of fans and pumps. In order to ensure the reliability of production, a variety of production machinery in the design of the power drive, have left a certain amount of surplus. When the motor can not run under full load, in addition to meet the power drive requirements, the excess torque increases the consumption of active power, resulting in a waste of electrical energy.
Fans, pumps and other equipment, the traditional speed control method is to adjust the inlet or outlet of the baffle, the valve opening to adjust the amount of air and water, its input power, and a large amount of energy consumption in the baffle, the valve in the interception process. When using frequency conversion speed control, if the flow requirements are reduced, by reducing the speed of the pump or fan can meet the requirements.
The use of frequency converters for electric motors is intended for speed regulation and to reduce the starting current. In order to produce variable voltage and frequency, the device first converts the alternating current of the power supply to direct current (DC), a process called rectification. The scientific term for a device that converts direct current (DC) to alternating current (AC) is "inverter".
Generally, an inverter is an inverter that inverts a DC power source to a certain fixed frequency and a certain voltage. For inverters with adjustable frequency and voltage, we call them inverters. Inverter output waveform is analog sine wave, mainly used in three-phase asynchronous motor speed with, also known as frequency governor.
For mainly used in instrumentation testing equipment in the waveform requirements of the higher variable frequency inverter, to organize the waveform, you can output a standard sine wave, called variable frequency power supply. General variable frequency power supply is 15 - 20 times the price of the inverter. Because the main device in the inverter equipment to produce a change in voltage or frequency is called "inverter", so the product itself is named "inverter", that is: inverter.
Inverter is not everywhere can save electricity, there are many occasions with inverter does not necessarily save electricity. As an electronic circuit, the inverter itself also consumes power (about 3-5% of the rated power). A 1.5 HP air conditioner itself consumes 20-30W, equivalent to a long light. Inverter running at industrial frequency, with power-saving function, is a fact.
But his prerequisites are:
First, high-power and fan/pump loads;
Second, the device itself has a power-saving function (software support);
These are the three conditions that reflect the effect of power saving. In addition, it does not matter whether the power saving, there is no meaning. If you do not add the preconditions that the frequency converter frequency operation energy saving, is exaggerated or commercial speculation. Know the original reason, you will skillfully use him to serve you. Must pay attention to the use of occasions and conditions of use in order to apply correctly, otherwise it is blindly, gullible and "cheated".
Power factor compensation energy saving
Reactive power not only increases line loss and equipment heating, more importantly, the reduction of power factor leads to a reduction in the active power of the grid, a large amount of reactive power consumption in the line, the use of equipment is inefficient, wasteful and serious, the use of frequency conversion speed control device, due to the role of the internal filter capacitor in the inverter, which reduces the reactive power loss, increasing the active power of the power grid.
Soft start energy saving
1, motor hard start on the grid caused by serious impact, but also on the grid capacity requirements are too high, the start of the high current and vibration on the baffle and the valve damage is very great, on the equipment, pipeline service life is extremely unfavorable. And the use of frequency conversion energy-saving devices, the use of inverter soft start function will make the starting current from zero, the maximum value does not exceed the rated current, reducing the impact on the power grid and the requirements of the power supply capacity, extending the service life of equipment and valves. Saves the maintenance cost of the equipment.
2, theoretically speaking, inverter can be used in all mechanical equipment with motor, motor in the start, the current will be higher than the rated 5-6 times, not only will affect the service life of the motor and consume more power. System in the design of the motor selection will leave a certain margin, the speed of the motor is fixed, but in the actual use of the process, sometimes to lower or higher speed operation, so the frequency conversion is very necessary. Frequency converter can realize motor soft start and compensate power factor.