Occasionally, there is a requirement for contactors with all or some of the main poles (main power contacts) in the N/C (normally closed) configuration.

Due to the relative rarity of applications that require N/C main poles, and secondly the technical challenge that designing a contactor with N/C poles poses, there is a smaller choice of products available in this format.

Products available from the Schneider Electric TeSys (former Telemecanique) contactor range with some or all of the contacts N/C;

• TeSys D contactors with the following part number format have 2 N/O and 2 N/C main poles; LC1D??8??
  Example part number#; LC1D128F7 specification; 2 N/O and 2 N/C main poles, rated 25A AC1 duty, 1 N/O + 1N/C auxiliary contacts, 110V ac coil.
  
• TeSys GC Modular contactors. These contactors are available in a variety of pole compositions including 1, 2,3 or 4 N/C and also in versions with both N/O and N/C poles. Maximum current rating with N/C poles is 63A AC-7a duty.
  Example part number#; GC6304M5 specification; 4 N/C main poles, rated 63A AC-7a duty, 220 / 240 V 50Hz ac coil.
  
• CV1 / CV3 variable composition 'bar and shaft' contactors. These contactors were custom built to order but unfortunately they are not available from Schneider Electric anymore. This particular range was sold to Lenoir Elect (https://www.lenoir-elec.com) so you can still get this particular offer from them.

#Note: To obtain further information, key this part number in to the search option (top right hand corner) of our web site; www.se.com/uk and click the search button.

If a suitable N/C contactor cannot be sourced, there are a couple of options that may be worth considering (suitability will very much depend on the application and would need to be verified by the electrical engineer responsible for the project);

• Use of a standard contactor with N/O (normally open) main poles held closed by the contactor coil*. This does not, however, address a requirement for the main poles to close on loss of a control supply.
• Use of a standard contactor with N/O (normally open) main poles held closed by a mechanical latch block. This solution requires the contactor to be energised conventionally via it's coil circuit, which closes the main contacts. Once closed the coil circuit is removed and the contactor remains closed by means of a mechanical latching mechanism. To open the contactor contacts, the mechanical latch block has another 'de-latch' coil. Again, this does not address a requirement for the main poles to close on loss of a control supply.

*Note: It is perfectly acceptable to energise a contactor coil for long periods providing precautions are taken (Observe all catalogue performance limits, particularly temperature and voltage limits, periodically cycle test the contactor by de-energising and re-energising the coil circuit).

Released for:Schneider Electric Ireland