Choosing VFD Cables
April 7, 2014
Why do you need VFD cables?
Here are some of the responses I hear when I ask what customers are using to connect a Variable Frequency Drive (Allen-Bradley PowerFlex 523, 525, 753, 755) to a motor:
- We use THHN in pipe, or
- We use shielded tray cable, or
- We use a motor supply cable… when connecting a VFD to a motor.
There are many reasons why I do not recommend using any of the above, and instead recommend Variable Frequency Drive (VFD) cables, this includes:
- VFD cables are used for VFD applications; THHN is a general building wire.
- VFD cables offers superior performance over THHN cables with industrial-grade XLPE insulation and are more reliable than THHN.
- VFD cables provide better protection with a shielding system when used in VFD applications for motors, bearings, drives, and related equipment.
- While shielded tray cables provide better insulation than THHN in pipe, they still do not compare in performance improvement and lack a shielding system to minimize radiated and conducted noise (which can disrupt plant control and instrumentation systems).
VFD cables provide protection and are specifically designed (higher stranding, robust insulation, better shielding) for installation between a VFD and a motor, reducing any downtime when using THHN or shielded tray cables.
Overall VFD cables are more reliable and offer better protection and improved performance over other cable options.
Below is a collection of videos provided by Omni Cable and Belden on VFD cables: