With the continuous advancement in the automation field, inverters have become deeply integrated into various industries and fields. Inverters are also constantly innovating, becoming more powerful in functionality and reliability as a result. However, improper use, incorrect operation, and inadequate maintenance can still lead to malfunctions or changes in operating conditions, which can shorten the lifespan of the equipment. Therefore, routine maintenance and inspection are particularly important.。
Important Notice: Operators must be familiar with the basic working principle and functional features of the variable-frequency drive, and possess basic electrical knowledge. Before inspecting and maintaining the variable-frequency drive, the main power supply to the equipment must be completely turned off.And perform under the condition that the variable frequency inverter light is completely off.
Pre-operational Inspection Items: Prior to powering on the variable frequency inverter, it is essential to check the surrounding environment's temperature and humidity. Excessive temperatures can lead to overheating alarms on the inverter, and in severe cases, directly cause damage to the inverter's power devices and circuit short-circuits.Excessive humidity can cause direct short circuits inside variable frequency inverters. When the inverter is operating, pay attention to whether its cooling system is functioning properly, such as: whether the air ducts are flowing smoothly, and if there are any abnormal sounds from the fan. Generally, inverters with higher protection levels, such as those above IP20, can be installed open, while those below IP20 are usually cabinet-mounted, so the heat dissipation effect of the cabinet will directly affect the normal operation of the inverter. Dewo variable frequency inverters utilize high-performance custom industrial-grade fans for stable cooling.
Regular maintenance includes cleaning the air filter, cooling air ducts, and internal dust. Check for loose screws, bolts, and connectors. Inspect the input-output inductors for any short-circuiting, which should normally be greater than several tens of megohms. Look for corrosion on conductors and insulators, and clean them with alcohol if necessary. If conditions permit, use an oscilloscope to measure the stability of the switch power supply output voltages, such as:5V, 12V, 15V, 24V, and other voltage levels. Measure the waveforms of each channel of the drive circuit for any distortion in the square wave. Verify if the UVW phase-separated waveforms are sine waves. Check for sparking marks on the contactor's contacts; replace with a new model or one with a higher capacity if severe. Confirm the accuracy of the control voltage and perform sequential protection action tests. Ensure there are no anomalies in the protection display circuit. Confirm the voltage balance of the inverter when operating independently. Recommend regular inspections, ideally once a year. Dewo inverters are professional-grade and withstand various harsh operating environments.
Four, the replacement of the variable frequency drive is composed of various components, some of which may gradually degrade and age after long-term operation, which is also a major cause of failure in variable frequency drives. To ensure the long-term normal operation of the equipment, the following components should be replaced on a regular basis:
The power module of a variable frequency drive cooler fan is a device that generates a significant amount of heat. The heat produced during continuous operation must be discharged promptly; typically, the lifespan of a fan is around 10K to 40K hours. When converted to continuous operation of the variable frequency drive, a fan replacement is necessary every 2 to 3 years. There are two-wire and three-wire direct cooling fans; the two-wire fan has one positive and one negative wire, and it's crucial not to connect them incorrectly during replacement; the three-wire fan has an additional detection wire, so great care must be taken during replacement to avoid triggering an overheating alarm on the variable frequency drive. AC fans usually come in 220V and 380V versions; ensure the voltage rating is not mixed up during replacement.
2. Intermediate Circuit Filter Capacitors: Also known as electrolytic capacitors, their primary function is to smooth out DC voltage and absorb low-frequency harmonics in DC. The continuous operation generates heat, along with the heat produced by the inverter itself, which accelerates the drying of the electrolyte, directly affecting the capacitor's capacity. Under normal circumstances, the lifespan of capacitors is 5 years. It is recommended to check the capacitor capacity at least once a year, and generally, if the capacity decreases by more than 20%, it should be replaced.
