Maintenance Precautions for Medium Voltage VFD

In the fault handling of the medium voltage VFD, the key to effectively improving the operation of the equipment is to be able to quickly determine the location of the equipment fault and deal with it effectively.

Although hazards vary by site and application, there are many things to consider when attempting to perform electrical maintenance. Medium voltage (MV) equipment poses an even greater risk to those unfamiliar with how it works, as such equipment is often not well understood. However, even a low voltage arc flash event can produce an event more powerful than a lightning strike, meaning that using switchgear, VFDs or any energized equipment can be a very dangerous task if workers are not properly trained and protected with proper PPE . Properly locking/tagging equipment that has proven to be de-energized will help ensure a safe work environment for the equipment and your employees.

1. Effective daily maintenance
Formulate corresponding maintenance manuals and specify routine inspection items, such as: cleaning the stopped VFD, testing the fan and pre-charging circuit of the VFD. Reserve spare parts to avoid major damages due to lack of spare parts in the event of a failure.

2. Training and education of personnel
The technical content of the medium-voltage VFD is relatively high. Since the high voltage in the DC bus in the VFD will cause serious harm to the human body, it is necessary to train the relevant maintenance personnel so that they can master the maintenance requirements of the VFD and the specific maintenance procedures. Matters needing attention, improve the technical level of maintenance personnel, so as to avoid secondary damage to equipment caused by maintenance personnel in equipment maintenance.

3. Do a good job in the dust treatment of the VFD
Medium voltage ac drive have relatively high requirements on humidity, dust and temperature. It is necessary to do a good job of dust accumulation in the VFD according to the actual operating conditions of the VFD. In places with high dust content, it is recommended to use a water-cooled VFD. A small amount of dry dust is allowed in the insulation gap of the VFD, but conductive dust must be avoided. Dust will accumulate in the air with high humidity, and the dust accumulation on the VFD must be dealt with. In particular, semiconductor device surfaces need to be kept clean, while fabric laminates for insulated posts and low-inductance busbar assemblies are kept dry and clean. During the maintenance of the VFD, you can choose a clean and dry cloth to wipe the surface of the cabinet. The cloth used for wiping should be made of lint-free materials. During the wiping process, change the surface of the cloth to ensure the complete removal of dust. If there is excessive dirt accumulation, you can add a small amount of alcohol to the cloth surface, you can use a brush and a vacuum cleaner, and for some inaccessible places, you can use compressed air. In the dust accumulation treatment, by checking the scale of the filter, if the dirt is found to block the air flow, you can choose to replace the filter sheet for treatment.