Variable Frequency Drives are widely used in industrial motor control applications such as fans, pumps, compressors and conveyors. In many industrial sites, VFDs operate in harsh environments with dust, humidity and unstable power supply. Proper protection is important to reduce downtime, improve reliability and extend service life.
1. Protect VFD from Dust
Dust can impact heat dissipation and lead to insulation difficulties, short circuits or component breakage. This is notably so in the case of cement industries, mines, steel plants and paper mills.
To minimise the dust the VFD should be installed in a clean, dry and well-ventilated electrical room. Do not place it near crushers, conveyors, mills or other equipment that produces a lot of dust. Regular cleaning of cooling fans, filters, air ducts and cabinet surfaces is recommended.
RENLE RNHV series medium-voltage VFD is IP30 standard protection class. Depending on the operational conditions even higher protection ratings can be specified.
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2. Stop Moisture and Condensation
Moisture can cause corrosion, the degradation of insulation and electrical failures. Condensation is much more hazardous, as water droplets can form on circuit boards, terminals or busbars.
The RNHV series medium voltage VFD must be operated in humidity levels between 5% and 95% RH, no condensation. Hence, the VFD room should be dry and ventilated and should be protected from rain water, steam, leaks and corrosive gases.
In high humidity or substantial temperature difference situations, air conditioners, dehumidifiers or cabinet warmers can be utilised to prevent condensation inside the cabinet.
3. Avoid voltage fluctuations reaching the VFD
Industrial sites frequently encounter unstable voltage, loss of phases, surge voltage or voltage dips. These faults might result in VFD tripping, motor shutdown, or equipment damage.
The RNHV series medium voltage VFD has an input voltage range of -10% to +10% and a frequency tolerance of ±2%. If the power grid fluctuates substantially, the power quality should be evaluated before starting operation. Power quality devices such as surge protection or input reactors may be needed.
The RNHV series features multi-protection functions such as overvoltage, undervoltage, surge voltage, overheat, short circuit, overload and phase loss prevention.
4. Allow adequate space for installation and cooling
A VFD gives off heat when it is working, so installation space and ventilation is quite crucial. Adequate room for heat dissipation and maintenance should be given. Do not install the cabinet too close to walls or heat sources.
Recommended clearance for RNHV series is minimum 0.5 m above the cabinet, 0.8 m at the back, 0.6 m per each side and 1.6 m in the front.
Daily Maintenance Tips
To improve VFD reliability, users should regularly check the following points:
Check whether the cabinet is properly sealed.
Clean filters, fans and air ducts.
Check cable entries for water or dust.
Review alarm records and fault history.
Check ambient temperature, humidity and ventilation.
Confirm that the grid voltage is within the allowed range.
