1. Check the actual site temperature
Don't just look at the average ambient temperature. You need to know the max temperature of the VFD cabinet especially during summer time or peak production.
Check before you choose a VFD:
Maximum temperature of the environment
Installation indoors or outdoors
Electric room air ventilation
Temperature inside the cabinet
Direct solar light exposure
Dust and humidity leve
A VFD may function fine at 35°C but may trip out often at 45°C and higher cabinet temperature.
2. Think about VFD Derating
The real output capacity of a variable frequency drive may be reduced by high temperature. This is referred to as derating.
Many users choose a VFD based on motor power only e.g. 250 kW or 1 MW. But for high temperature situations, you should also examine rated current, overload capacity, cooling condition and derating curve.
A safer choice should take into account:
Motor nameplate current
Load type
Normal or heavy duty operation
Needs for overloading
Continuous run time
Derating ambient temperatur
If you are selecting a VFD for severe environment it is more reliable to select one with ample margin of current rather than one that simply meets the motor power.
3. Choose the Right Cooling Method
Air-cooled VFDs are appropriate for many common industrial applications. They are basic, inexpensive and easy to maintain. But they need sufficient ventilation and a clean circulation of air.
Air cooling should be used when:
The electrical room is well ventilated
Dust level is manageable
Filters can be cleaned regularly
Ambient temperature is not extremely high
The cabinet has enough space for heat dissipation
Regular maintenance can be performed on fans and filters
For high-power motors, dusty operations or hot conditions, water cooled VFDs might be a preferable alternative. They are rugged and built for industrial settings with minimised heat inside the cabinet.
Water cooling is commonly advised for:
High-power motors
High ambient temperature
Heavy dust environments
Limited electrical room ventilation
Continuous 24/7 operation
Medium voltage VFD systems
4. Pay Attention to Cabinet and Protection Design
A good VFD can still fail if the cabinet design is poor. In high-temperature sites, the cabinet must remove heat efficiently and protect internal components from dust, moisture, and pollution.
Important cabinet factors include:
Air inlet and outlet corrected
Cabinet space enough
Design of anti-dust filter
If necessary heat exchanger or air conditioner
High level of protection
Anti-condensation design
5. Match the VFD to the Load Type
Different loads have different requirements , and the VFD should be selected according to the actual working condition of motor and equipment . Fans and pumps are usually easier to control because they have a relatively constant torque demand . But the crushers, mills, conveyors, compressors and extruders have higher requirements for starting torque, overload capacity and control performance of acceleration and speed change.
Before ordering a VFD, it is important to determine the type of load, starting torque requirement, speed regulation range, acceleration time, overload frequency, and whether the equipment is running continuously or intermittently. The VFD should have the greater thermal capacity and enough overload margin for heavy-duty loads in high-temperature environment to prevent over-temperature fault, unstable operation or unexpected shutdown.
6. Consider Long-Term Reliability
Cheapest VFD is not always the best VFD for industrial projects. The cost of one unplanned shutdown in high temperature applications can be significantly more than the price difference between two VFD models. The reliability of VFDs for continuously operating equipment directly affects production stability, maintenance planning and total operating cost.
A good selection of VFD should reduce over temperature trips, emergency maintenance, production down time, spare parts replacement, cabinet modification cost and commissioning problems. The right VFD for B2B buyers should be selected based on lifecycle cost and long-term operating reliability, not just the initial purchase price.
Why Choose RENLE?
RENLE offers low-voltage and medium-voltage VFD solutions for tough industrial applications. Our VFD products are available in a wide range of power and voltage, air cooled, water cooled, high protection and containerised solutions.
RENLE can provide customised VFD solutions for high ambient temperature, heavy dust, humidity and harsh working conditions for industries such as cement, mining, metallurgy, oil and gas, petrochemical, water treatment and power generation.
RENLE cares not only about the VFD itself, but also about system integration, cooling design, cabinet protection, commissioning support and long-term reliable operation.
