Proper termination of variable frequency drive (VFD) cable is essential to realizing the benefits that can be achieved from using this special cable. These benefits include reducing electromagnetic interference (EMI), minimizing ground currents, controlling common mode current (which if left uncontrolled can damage motor bearings), and more. These benefits result in reduced downtime, fewer drive trips, and improved system performance. These benefits, however, can only be achieved through proper termination of the cable.
Southwire Company, LLC has a great application note on VFD cable termination, titled Begin with the End in Mind – Proper VFD Cable Termination. While that application note discusses the basics, it only addresses the simple system involving a drive, a motor, and a cable connecting them. If that’s the system you have, that application note is all you need. But many systems are more complex. Some systems involve a quick disconnect between the drive and the motor. Other systems may have a junction box between the drive and the motor. And still other systems might have both. In cases like this, it is important to know how to handle cable termination into and out of these additional components.
