Wind · European-built turbines in the US
Wind turbine breaker and contactor repair for US fleets
The 690 V main breaker and the generator, grid and crowbar contactors in a European-built turbine are IEC-frame units. We strip them, rebuild them to OEM wear limits, injection-test them and fly them back to your site with the certificate. For fleets, a tested exchange unit can leave the UK the day a fault is reported.*
- Main breaker690 V ACB, typically 800–2500 A
- Door to doorAbout 8–11 working days
- Exchange unitsShipped the day a fault is reported*
- Warranty24 months on overhauls
The duty
A turbine breaker works harder than its datasheet expects
The main incomer in an office building might open and close a dozen times a year. The generator breaker in a wind turbine can do that in a week. It switches on every cut-in and cut-out, every grid event and every curtailment. The converter contactors and the crowbar behind it cycle harder still.
Then add the environment. The tower and drivetrain put constant low-frequency vibration into the cabinet. Daily temperature swings pull condensation onto the mechanism and the trip-unit electronics. Converter current carries harmonics that heat contacts and terminations and can confuse older trip units. Coastal sites add salt.
The wear that follows is predictable. Charging motors give out. Grease hardens until the mechanism closes slowly or not at all. Contacts erode faster than the maintenance plan assumed. Trip units drift or nuisance-trip on start-up current. None of that is a reason to scrap a breaker with a sound frame and sound arc chutes. It is a reason to rebuild it.
What we repair
The LV switchgear in the turbine base
Three groups of equipment, one workshop process. Every unit is stripped, measured against OEM wear limits, rebuilt and tested before it ships.
The 690 V main breaker
The generator or main ACB between generator, converter and transformer, typically 800 to 2500 A, usually motor-charged so the controller can open and close it remotely. Mechanism rebuild, main and arcing contacts, charging motor, coils, trip unit and a full secondary injection test.
ABB SACE Emax · Emax 2 · Masterpact NW/NT · Siemens 3WL · Eaton IZM
Grid, generator and crowbar contactors
The large-frame contactors that connect the stator and rotor circuits and switch the crowbar, cycling on every start and stop. Contact sets, coils, pole carriers and arc chutes, tested for pick-up, drop-out and contact resistance.
Schneider TeSys LC1F · ABB AF / A-series · Siemens 3RT / 3TF
First-generation units
Turbines commissioned in the 2000s often run breakers and contactors the OEM no longer makes. Donor stock and re-machined parts keep the original in its cell, so there is no cabinet change and no controller rewiring.
First-generation Emax · Masterpact M · early 3WL · TeSys F
Why a UK workshop
The turbine is European. So is its switchgear.
Vestas, Siemens Gamesa, Nordex and the older GE platforms built on European designs arrived in the US with the LV breakers and contactors their engineers specified: Emax, Masterpact, 3WL, LC1F. Here those are IEC-frame units, and the domestic service channels are set up for the North American ranges. Repair capability for the IEC frames is thin, and for the first-generation units it is close to absent.
Our workshop in Yorkshire, England, repairs these ranges every day. A turbine breaker from Iowa or Texas is the same job as one from a UK site, with a crate and a commercial invoice added. We arrange the air freight and prepare the paperwork, and you choose whether we ship DAP or DDP.
Exchange units
One climb, not a fortnight of lost generation
Bench time is rarely the critical path on a turbine. The critical path is the fault, the climb to confirm it, the climb to remove the unit, the freight both ways and the climb to refit. Across all of that the turbine produces nothing.
An exchange unit cuts the sequence short. We hold many tested units in the UK*. When a fault is reported and the model is in stock, a unit set to your protection settings ships by air the same day. Your technician fits it, and the failed unit comes back to us for rebuild.
- Overhauled, injection-tested and certified before it leaves the shelf
- Set and tested at your fleet's protection settings
- Failed unit rebuilt afterward, with a strip-down report so failure patterns across the fleet are visible
*Subject to model and rating.
Fleets
Set up per fleet, per model
For a fleet, exchange works best when it is planned. We start from the turbine models, the breaker and contactor part numbers, ratings, trip units and settings, either from your asset register or from nameplate photos on the next round of climbs. Most fleets need one or two units per model, not one per turbine.
The pool can be built from your own spares, overhauled and certified here, or from donor units we rebuild. Ownership is agreed at the start. Units can also be shipped to your central stores and replenished as failed units come back.
When a fleet has too many units to fly economically, our engineers can travel to the US and do the repairs on site. On-site in the US.
Case study
A seized 3WL from a US wind farm, rebuilt in four days
A 2500 A Siemens 3WL with an ETU45B trip unit arrived with its mechanism seized solid, broken internal plastics, a snapped charging handle and carbon from pole L1 into the arc chute. It was stripped to the frame, rebuilt, injection-tested and on its way back by air four days after it reached the workshop.
Proof
A certificate your engineer can check
Breakers
Secondary injection against the published trip curve for every enabled protection element, contact resistance per pole, insulation resistance and mechanical operation, recorded against the serial number.
Sample ACB certificateContactors
Coil resistance, pick-up and drop-out voltage, operation at 85% coil voltage, contact resistance per pole and insulation resistance.
Sample contactor certificateWarranty
24 months on full overhauls and refurbishments, 12 months on repairs. Before and after photos and a parts list come with every unit.
WarrantyFAQ
Wind questions we get asked
The OEM says our turbine breaker is obsolete. Do we have to replace it?
No. Obsolete means the OEM has stopped making it, not that it can't be repaired. First-generation Emax, Masterpact M and early 3WL units are rebuilt with donor and re-machined parts and go back into their own cell, with no adapter plates and no change to the controller wiring.
Do we need to send the cradle as well as the breaker?
Usually not. Send the moving portion, and email photos of the cradle, the secondary disconnect and the cell with the nameplate. If the strip-down points to a cradle fault, we'll tell you.
The breaker nuisance-trips on start-up. Is it faulty?
Sometimes. Converter start-up current is rich in harmonics, and an older or drifting trip unit can read it as a fault. Injection testing shows whether the unit is out of tolerance. If it isn't, the answer is a settings review, and we'll say so rather than rebuild a breaker that didn't need it.
Can the unit come back set to our protection settings?
Yes. Send the settings from the turbine documentation or the existing unit. The breaker is set to them and injection-tested at those settings, and the certificate records them.
How long does a repair take door to door?
About 8–11 working days plus customs clearance on the standard service: 3 days' air freight each way and 2–5 working days in the workshop. Express cuts the workshop time to 1–2 days. If you can't wait that long, ask about an exchange unit.
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.