Case study · contactor · Denmark / USA
An arc-damaged LC1F780 contactor, restored in one week
A Schneider TeSys F LC1F780 arrived after an arc flash: carbon everywhere, copper terminals welded together, one coil dead. One week later it was dispatched with its contacts separated, re-plated and restored and the failed coil replaced, on a range the manufacturer no longer supports.
- UnitSchneider TeSys F LC1F780 · 780 A
- FaultArc flash, welded terminals, carbon
- Turnaround1 week, arrival to dispatch
- OutcomeBack in service, obsolete coil replaced
Case file
Summary
| Customer | A repair company with operations in Denmark and the United States, needing a route for an obsolete Schneider frame. |
| Problem | High-current contactor not operating after an arc-flash event. |
| Unit | Schneider TeSys F LC1F780, a 780 A high-current contactor from a range that is now obsolete. |
| Diagnosis | Severe arc-flash damage and carbon contamination across the pole assemblies. Copper terminals welded together. One internal coil failed. |
| Repair | Broken down to individual components, every part cleaned, welded contacts separated, re-plated and restored, failed coil replaced, unit rebuilt. |
| Testing | Pick-up and drop-out voltage, contact resistance per pole, insulation resistance, coil current and mechanical operation, all recorded on the certificate. |
| Turnaround | One week from the day it arrived to the day it was dispatched. |
| Logistics | Import and export handled by us, including the repair-and-return customs paperwork, so the customer dealt with one supplier rather than a freight forwarder. |
| Outcome | Ready to go straight back into service. No replacement cost, no long lead time, no obsolescence problem. |
As received
Welded shut, black with carbon, out of production
An arc flash inside a contactor does two kinds of damage. It throws carbon over every insulating surface: the pole carriers, the arc chutes and the molding between phases. And it melts the contact faces, so that when the arc clears the copper has fused together.
This unit had both. The terminals were welded, the pole assemblies were blackened from end to end, and the contactor would not operate.
The frame made it harder. The TeSys F range has been obsolete since 2023, and Schneider's own guidance is that LC1F contactors cannot be repaired. The customer's usual answer, ordering a new one, meant a long wait for a discontinued part or an engineering change to fit a current replacement. Either way, a job moving between Denmark and the US would have stalled for weeks.
The work
Down to components, and back up in a week
Break down
Pole assemblies, contact carriers, springs, arc chutes, magnet and coil all off the frame. Nothing cleaned in place, because carbon hides in every joint.
Clean
Carbon removed from every molding and metal surface, then the insulation checked for tracking before any part went back.
Restore contacts
Welded faces separated, dressed back to true and re-plated so the poles carry rated current without heating.
Replace the coil
The failed coil sourced and fitted despite the obsolete range, and the magnet faces cleaned so the contactor pulls in without chatter.
Test and ship
Pick-up, drop-out, contact resistance, insulation, coil current and operation proved on the bench. Dispatched one week after arrival.
Outcome
A small repair, not a replacement project
The contactor went back ready to fit: same frame, same footprint, same terminations, no engineering change. The customer avoided both the cost of a replacement and the wait for a discontinued part.
Because we handled the import and export at our end, what could have been a shipping exercise across two countries became a single repair order with one supplier. One week in the workshop, arrival to dispatch.
For your LC1F contactors
Frames from 265 A to 2100 A
- Contacts, pole carriers, springs, arc chutes, coils and auxiliary blocks
- Coil resistance, pick-up, drop-out and operation at 85% coil voltage on the certificate
- Before and after photos and a parts list with every unit
- You choose DAP or DDP; we prepare the commercial invoice and repair-and-return paperwork
Send yours
An obsolete contactor shouldn't stop a job
Send the nameplate, a photo of the contactor and a description of what happened. We reply the same working day with a recommendation and a price for diagnosis and freight. Standard service is about 8–11 working days door to door plus customs clearance, and Express gives a 1–2 day workshop turnaround.
Send us the nameplate
A photo of the nameplate and the fault is enough for a first answer. We reply the same working day with a recommendation and a price for diagnosis and freight.