Frequency converter type：
By changing the stator supply voltage frequency to make the speed smooth change of the method known as variable frequency speed regulation.The device that realizes frequency conversion speed regulation to ac motor is called frequency converter.There are two kinds of inverters: alternating current inverters and alternating current inverters
Sinusoidal pulse width modulation (SPWM) frequency conversion technology
At the same time of changing the voltage frequency, the output voltage can be changed by changing the width of the output pulse, so as to meet the requirements of variable frequency speed regulation on U/ coordinated control.The pulse width is sinusoidal throughout the half - cycle.That is, the pulse width increases gradually first, then decreases gradually;And the corresponding output voltage will also change according to the sinusoidal rule.This is the sinusoidal pulse width modulation (SPWM) frequency conversion technology which is most widely used in engineering practice.
Installation method of inverter:
(1) when multiple frequency converters are installed in the same electrical cabinet, they are usually placed horizontally.The space inside electric cabinet is small, need to carry on longitudinal when put, because the heat of the lower frequency converter can cause the temperature rise of the upper frequency converter to cause the frequency converter fault, should adopt to install guide board and so on countermeasure.
(2) the lower part of the converter is the wiring space, and the upper part is the heat dissipation space:
For easy cooling and maintenance, there should be enough space around the converter to keep it separate from the walls of other devices and disks.
(3) the upper part of the converter has a small fan built in the unit to ensure that the heat inside the converter rises from the bottom to the top. If the upper part is equipped with a device, it should be ensured that no fault will occur even if it is affected by heat.The heat generated inside the converter flows from the lower to the upper part of the unit as warm air through the cooling fan.When installing a fan for ventilation, consider the direction of the wind to determine the installation location of the ventilation fan
Daily maintenance methods：
(1) routine inspection：
Always check the operation of the motor is abnormal.Whether the port installation environment is suitable.Whether the cooling system is abnormal.Whether the mouth has abnormal vibration sound.Whether the mouth is overheating and discoloration.The multimeter is used to measure whether the input voltage of the converter is normal.
(2) regular inspection
Cooling system: clean air filter, etc.
Screws and bolts: due to vibration, temperature change and other reasons easy to cause the loosening of screws and bolts and other fasteners, it is necessary to regularly check whether these fasteners are tightened reliably.
Conductor and insulating material: check for corrosion and damage.
Measure insulation resistance.
Check and replace cooling fans, relays, etc.