Industry: Industrial Manufacturing
Focus: VFD Cable Installation, Motor Protection
Author: Will Morris, Associate Product Manager
The Problem: “We were killing motors from the inside out.”
For three years, Summit Paper Mill couldn’t explain why their 250 HP fan motors failed every 14 months. Not winding burnout. Bearing failure. Pitted races, fluted surfaces, metallic debris in lubricant.
The cost was staggering:
- $47,000 per motor replacement
- 8 hours downtime at $12,000/hour
- Four motors in 24 months = $188,000 in hardware
- $384,000 in lost production
And nobody knew why.
The invisible culprit: grounding glands. Standard practice. Stripped the shield at each motor, creating a common mode current (CMC) loop. VFD switching noise found a path through motor bearings instead of back to the drive. Every pulse carved microscopic pits. Damage accumulated silently until failure.
The same glands leaked EMI into the plant. PLCs faulted intermittently. Wireless sensors dropped. The team chased ghosts while the real enemy sat at every motor connection.
“We bought ‘industrial-grade’ VFD cable. Used termination kits. Followed the manual. But grounding glands created a closed circuit using our bearings as the return path. Nobody told us.”
The breaking point: Motor five failed at 11 months. Warranty denied. Bearing analysis confirmed electrical discharge machining (EDM) damage. The motor was fine. The installation was not.
The Solution: “One Gland. Everything Protected.”
A cable specialist asked one question nobody had: “Why are you stripping the shield?”
The fix: switch to isolating glands.
Shield continuity preserved. The isolating gland keeps the cable shield intact all the way to the drive. Noise returns safely, not through bearings, not into the plant.
- CMC loops eliminated. No local ground point at the motor. Bearing currents drop to negligible.
- No termination kit required. Grounding glands strip the shield and need kits to manage the mess. Isolating glands don’t. So no kit, no extra parts, no extra labour.
- Class 1 Div 2 rated. UL-listed with E-file reference. Critical for Summit’s pulp processing areas.
- Install time cut 55%. Each termination dropped from 45 minutes to 20. No kit assembly. No shield braiding. No guesswork.
“The first motor we protected had been scheduled for replacement in Q3. It’s now 22 months old, vibration cleaner than new. We didn’t fix a failure mode. We eliminated it. Lead Electrical Engineer, Summit Paper Mill
Client Feedback: “The cheapest fix we never tried.”
“Four motors at $47,000 each. Eight hours downtime at $12,000/hour. Termination kits at $180 per motor. Grounding gland ‘savings’ cost us half a million in two years. The isolating gland cost $12 more per fitting. The math is offensive.”
“PLC faults dropped 80% in the first month. Wireless sensors that dropped twice a shift now run uninterrupted. We were chasing EMI ghosts that our own glands created.”
“Class 1 Div 2 rating sailed through inspection. The grounding glands would have needed replacement anyway for compliance.”
“My electricians love it. No termination kit means no small parts to drop, no braid to unravel. Training new techs takes half the time.”
Growth: From Motor Rescue to Plant Standard
Month 1 to 3: All critical motors converted. Zero bearing failures. PLC faults and wireless drops eliminated.
Month 4 to 6: Isolating glands written into engineering standards. Grounding glands banned. Procurement consolidated.
Month 7 to 12: Standard applied to all new VFD installations: conveyors, pumps, agitators. Predictive maintenance launched using clean vibration data. MTBF extended from 14 months to projected 60+ months.
Year 2: VFD cable health monitoring integrated into CMMS. Shield continuity tested during outages. Bearing current measurements confirm near-zero EDM. Plant reliability metrics best in company history.
“We started trying to stop motors from failing. We ended with an installation standard that protects every rotating asset, cleans up our electrical environment, and simplifies every technician’s job. The isolating gland isn’t a fitting. It’s a philosophy.”
Maintenance Manager, Summit Paper Mill
Correct gland selection is the single most impactful decision in VFD installation. Isolating glands protect bearings, eliminate interference, reduce labour and remove termination kits.