What could be possible causes for VFD drives motor overheating
Many variable frequency drives come with an algorithm that CALCULATES a thermal rise based on load vs. speed. They are notoriously inaccurate! If the motor is NOT getting excessively hot AND the motor control is protected/interlocked with motor thermal switches then I have seen many times where the VFD comes with the ability to DISABLE the Electronic Thermal Overload which is merely a CALCULATED event and is NOT based on any special hardware in the motor.
This shows how complex a VFD can be if you do not understand the Inverter process. Several questions have to be answered before determining what could be possible causes for motor overheating. What load is the motor running at with the low frequency? Do you have VFD drive curves that show how the drive reacts to differing loads at low frequency? Do you have access to the firmware control diagrams that shows how the fault is generated? True, there can be an algorithm that generates this fault. However, there are many inputs to the algorithm that comprise the fault. If you look at variable frequency drives there are many things that have to be considered.
This shows how complex a VFD can be if you do not understand the Inverter process. Several questions have to be answered before determining what could be possible causes for motor overheating. What load is the motor running at with the low frequency? Do you have VFD drive curves that show how the drive reacts to differing loads at low frequency? Do you have access to the firmware control diagrams that shows how the fault is generated? True, there can be an algorithm that generates this fault. However, there are many inputs to the algorithm that comprise the fault. If you look at variable frequency drives there are many things that have to be considered.
