Industrial Engineer · phase 13 of 16
Shielded VFD Cable
Motor cable designed with suitable insulation and a continuous low-impedance shield or armor for PWM drive service.
The Explain card
- Plain English
- VFD cable is motor cable built for PWM. It has insulation rated for the voltage peaks, a continuous copper shield or armor, and usually three symmetrical ground conductors, so the high frequency current has a low impedance path back to the drive.
- Example
- A drive is installed with ordinary building wire in conduit. Nearby instruments misbehave, the ground fault trips, and the motor bearings fail. The cable is replaced with shielded VFD cable and all three problems ease.
- Why it matters
- The cable is the return path for common mode current, and an unshielded run turns the whole plant grounding system into that path. Buying the right cable is cheaper than diagnosing what the wrong one does.
- Hook
- The cable is part of the drive.
Where it sits in the deck
Phase 13: VFD Power Quality, Wiring, and Motor Protection
Harmonics, reflected waves, shielded cable and bearing currents: the side effects a drive inflicts on everything around it.
