Should a variable-speed AC motor be fitted with a mains filter
Most frequency inverters for motors have built-in mains filters designed for Class A limits (industrial environments) but do not cater for Class B limits (domestic or light industrial environments).
The instruction manual will normally stipulate the maximum length of motor cable that can be used.
Variable-speed AC motor drives must be fitted with mains filters if the cable length and operating environment are different from those specified in the manufacturer's installation instructions. And the filter bodies must make direct metal-to-metal connection with the same metal plate that the drive’s heatsink is mounted on.← Back to FAQs