Case studies · from the workshop bench
Case studies: breakers and contactors we've brought back
What arrived, what we found, what we did and how long it took, with our own photographs from the bench. Plus two anonymized test certificates so you can see exactly what comes back with your unit.
- Case 01Siemens 3WL · US wind farm
- Case 02LC1F780 · arc damage
- CertificatesEmax E3N-A · LC1F780
Air circuit breaker · US wind farm
A seized Siemens 3WL, rebuilt for a US wind farm
A 2500 A 3WL with an ETU45B trip unit arrived with its mechanism seized by corrosion, broken internal plastics, a snapped charging handle and carbon from pole L1 into the arc chute. Stripped to the frame, every part cleaned, rebuilt, injection-tested and dispatched four days after it reached the workshop.
Contactor · Denmark / USA
An arc-damaged LC1F780, restored in one week
An obsolete Schneider TeSys F LC1F780 came from a repair company working in Denmark and the US after an arc flash: carbon across every pole, copper terminals welded together, one coil failed. Contacts separated, re-plated and restored, the coil replaced, and the unit dispatched one week after it arrived.
Sample certificates
What comes back with your unit
Two real certificates, anonymized. Every result is printed beside its tolerance band, so your engineer can check it rather than take our word for it.
Air circuit breaker
ABB SACE Emax E3N-A, 2000 A
A UL-listed power circuit breaker built to ANSI C37.13, with a PR122/P LSI trip unit. It arrived with a broken charging handle, a missing CLOSE button and corrosion throughout. The mechanism was fully dismantled, cleaned and rebuilt, and the closing, shunt and undervoltage coils replaced.
The certificate shows secondary injection results for L, S and I with the ABB Ekip SIM test kit, contact resistance of 14, 10 and 13 µΩ at 10 A, and insulation above 1000 MΩ at 500 V.
Contactor
Schneider TeSys LC1F780, 780 A AC-3
One pole carrier with severe arc damage and burnt moving contacts, plus surface rust on the drive shafts. The damaged parts were repaired, dressed and refitted across all three poles, and the mechanism cleaned and re-lubricated.
The certificate records coil resistance of 9.6 Ω, pick-up at 90 V, drop-out at 65 V, operation at 93 V (the 85% test), and contact resistance of 0.073, 0.071 and 0.057 mΩ at 10 A DC.
Your unit next
Every repair gets the same record
Each case study starts the same way: a nameplate photo and a description of the fault. Every unit we return, case study or not, leaves with an injection-test certificate, before and after photos and a parts list, under a 24-month warranty on full overhauls or 12 months on repairs.
By range
- Siemens 3WL, all frame sizes
- Schneider TeSys LC1F, 265–2100 A
- ABB SACE Emax E1–E6 and Emax 2
- Masterpact M and Masterpact NW & NT
- Eaton / Moeller IZM
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.