Maintenance of Shandong Inverter: Low voltage of frequency converter mainly refers to low voltage of central DC circuit. Usually, the reason of low voltage of central DC circuit comes from two aspects:
1. The low voltage from the input side of the power supply is 380V under normal conditions. The promised error is -15%~10%. After three-phase bridge full-wave rectification, the central DC voltage is 513V. In a single case, the smaller voltage swing of the power supply line will not cause the low voltage trip of the converter, as long as the effective value of the grid voltage is between 80%~85% of the additional value and lasts for a long time. More than one cycle will lead to the action of the converter. The low voltage on the input side of the power supply is mainly due to the fluctuation of the grid voltage or the switching of the main power line, the influence of lightning stroke on the sinusoidal amplitude of the power supply, and the overload or unbalanced load of the transformer in the power plant itself.
2. The low voltage from the load side is mainly caused by the start and use of large equipment, line overload or the start of large motors.
变频器是由整流器和逆变器两部分构成。通过对变频器的研究，document.write(') 变频器低电压 document.write(') 指其中心直流回路低电压(即逆变器输入电压过低)。通常的变频器都具有过压、失压和刹那间停电的维护功能。变频器的逆变器件分为GTR和IGBT两种，变频器的逆变器件为GTR时，一旦失压或停电，控制电路将中止向驱动电路输出信号，使驱动电路和GTR全部中止工作，电动机将处于自在制动状况。逆变器件为IGBT时，在失压或停电后，将答应变频器持续工作一个短时刻td，若失压或停电时刻totd，变频器自我维护中止运转。通常td都在15~25ms，而电源"晃电"时刻to通常都在几秒钟以上，变频器均会自我维护中止运转，使电动机中止运转。
Inverter is composed of rectifier and inverter. Through the study of the converter, document. write (') low voltage document. write (') refers to the low voltage of the central DC circuit (that is, the input voltage of the inverter is too low). Usually, the frequency converter has the maintenance function of overvoltage, voltage loss and instantaneous power outage. Inverters of frequency converter are divided into GTR and IGBT. When the inverter of frequency converter is GTR, once the voltage is lost or the power is cut off, the control circuit will stop output signal to the driving circuit, so that the driving circuit and GTR all stop working, and the motor will be in self-braking condition. When the inverter is IGBT, after voltage loss or power failure, the converter will be allowed to continue working for a short time td. If the voltage loss or power failure time totd, the converter self-maintenance will stop running. Td is usually between 15 and 25 ms, and the "power shake" time to is usually more than a few seconds, the frequency converter will self-maintenance stop operation, so that the motor stop operation.