Guide · Schneider TeSys F
Can a TeSys F (LC1F) contactor be repaired?
Schneider's position is no: the range is obsolete and the contactors are not treated as repairable. In a workshop, an LC1F is stripped, rebuilt and proved by test like any other high-current switching device. Here is what that involves.
Schneider's position
TeSys F is Schneider's range of high-current contactors, sold as LC1F115 up to LC1F2100. It sits in a large share of European-built machinery: generator sets, compressors, drive cabinets and wind-turbine converters. Plenty of that equipment is in service in the US.
Schneider's published FAQs say three things about it:
- The range is obsolete. TeSys F has been obsolete since the beginning of 2023, with some exceptions for specific application contactors.
- The replacement is TeSys Giga. That is the current-generation high-current contactor range.
- LC1F contactors are not treated as repairable. Schneider's reasoning is economic: repairing one generally costs more than manufacturing one. It does still list spare contact sets and coils for the range, so contacts and coils can be changed as maintenance.
From a manufacturer's point of view, that position makes sense. A factory builds new units; it does not run a strip-down bench. From a site's point of view, the picture is different. A failed LC1F780 in a turbine or a compressor panel is a stopped machine, and a TeSys Giga is a different contactor. Fitting one is an engineering change: mounting, busbar connections and control wiring all need checking before you can assume it is a drop-in.
What actually wears out in an LC1F
The TeSys F is well made, and it wears in well-understood ways:
- Main contacts. The silver-alloy faces erode and pit until the poles run hot or weld.
- Contact springs lose pressure, which raises contact resistance and heat.
- Pole carriers. An arc event can burn the carrier as well as the contacts, and carbon tracks across the moldings.
- The coil. LX1F coils overheat in warm cabinets or fail on a control-supply transient.
- Magnet faces pick up debris, and the contactor chatters.
- Auxiliary blocks go intermittent and send false signals to the controller.
None of these condemns the frame. The frame, the magnetic circuit and the housing are rarely the problem.
What a workshop repair involves
1. Strip to components
Pole assemblies, pole carriers, moving and fixed contacts, springs, arc chutes, magnet and coil all come off the frame. Nothing is cleaned in place, because carbon hides in every joint.
2. Clean and inspect
Carbon and corrosion are removed from every molding and metal surface. Insulation is checked for tracking before any part goes back.
3. Contacts and pole carriers
Each pole has fixed contacts and a moving contact on a carrier. Depending on what is found, contacts are replaced as sets, or dressed back to true and restored. Damaged pole carriers are repaired or replaced, using donor stock where new parts are not available. Contact alignment is checked across all three poles.
4. Coil and magnet
The coil is tested for resistance and insulation. A failed or marginal coil is replaced, and the magnet faces are cleaned so the contactor pulls in cleanly without chatter.
5. Mechanism and auxiliaries
The drive shafts and moving parts are cleaned and re-lubricated. Auxiliary blocks are checked in both positions and replaced if they are intermittent.
How the repair is proved
A contactor that closes is not the same as a contactor that works. Every LC1F we repair is tested as a unit, and the results go on a certificate against its serial number. Here is a real example, from an anonymized certificate for an LC1F780 (LC1FDP780A): 780 A AC-3, 1600 A AC-1, 3-pole, 110/120 V coil.
As received, one pole carrier had severe arc damage and burnt moving contacts, and the drive shafts had surface rust. The damaged pole carrier and moving contacts were removed, repaired, dressed and refitted across all three poles, contact alignment was checked, and the mechanism was cleaned and re-lubricated. Then it was tested:
| Test | Result |
|---|---|
| Coil resistance | 9.6 Ω |
| Coil insulation resistance | >1000 MΩ |
| Pick-up voltage | 90 V |
| Drop-out voltage | 65 V |
| Operation at 85% voltage | Operated at 93 V |
| Contact resistance, closed, at 10 A DC | 0.073 / 0.071 / 0.057 mΩ |
| Insulation resistance at 500 V DC | >1000 MΩ phase–earth and phase–phase |
| Operations | 30 electrical and 30 mechanical |
Pick-up below the coil's rating matters because it shows the contactor will still close when the control supply sags. Drop-out shows it will release when commanded. Balanced contact resistance across the three poles shows they will share current and run cool. The full certificate is on our sample contactor certificate page.
When a repair is not the right answer
- Small frames. On LC1F115 and LC1F150, a new contactor is often the better call where one can still be bought. We will say so.
- Repeated welding on the same duty. A repair replaces the welded contacts, but if the frame is undersized for the inrush, or the coil supply dips under load, it will happen again. The strip-down report will point to the cause.
- A planned upgrade. If the panel is being redesigned anyway, moving to TeSys Giga as part of that work can make sense.
Getting an LC1F to us from the US
Send a photo of the nameplate (the full LC1F reference and the coil voltage) and describe the fault. We reply the same working day. The contactor flies to our UK workshop in about 3 days, is stripped and quoted, repaired in 2–5 working days depending on severity (1–2 days on Express) and flown back with the certificate, before and after photos and a parts list. If you have a fleet, we hold many tested units in the UK* and can ship an exchange unit by air the day a fault is reported, if the model is in stock.
*Subject to model and rating.
Frequently asked questions
Is the TeSys F (LC1F) range obsolete?
Yes. Schneider's FAQ says TeSys F has been obsolete since the beginning of 2023, with some exceptions for specific application contactors, and names TeSys Giga as the replacement range.
Does Schneider still sell LC1F spare parts?
Schneider's FAQs list spare contact sets and coils for the range. Each pole's contact set is made up of fixed contacts, a moving contact, deflectors and a backplate. Other parts, such as pole carriers, are not covered, which is where donor stock and workshop repair come in.
Is TeSys Giga a drop-in replacement for an LC1F?
Do not assume it is. It is a different contactor, so mounting, busbar connections and control wiring all need checking. Repairing the LC1F keeps the original footprint and terminations.
Which LC1F sizes can be repaired?
We work on TeSys F frames from LC1F265 to LC1F2100. On the smallest frames, a new contactor is often the better answer where one is available, and we will tell you if so.
How do I know a repaired contactor is reliable?
Every unit is tested for coil resistance and insulation, pick-up and drop-out voltage, operation at 85% of coil voltage, contact resistance per pole and insulation resistance, then operated electrically and mechanically. The results are on the certificate.
For frame sizes, common faults and what an overhaul replaces, see our LC1F contactor repair page. To get a price, send the nameplate and the fault through request a quote.
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.