Schneider Electric LA1KN20 TeSys K 2 NO Front Contact Block

LA1KN20: two normally open contacts for status and self-hold circuits

The LA1KN20 is a Schneider Electric TeSys K auxiliary contact block with two normally open contacts for mounting on the front of the contactor. Normally open contacts close with the contactor, so the block is the usual accessory for a self-holding circuit and for a closing signal to a PLC or lamp. Seven Star LLC supplies the LA1KN20 in Oman and the GCC as an independent supplier based in Muscat.

Reading the reference: 20 is two NO and zero NC. As with the LA1KN02, the datasheet adds CA4K to the compatible list, together with LC1K, CA2K and CA3K.

Technical specifications of the LA1KN20

Compatibility and limits of the LA1KN20

Range compatibility from the datasheet: TeSys K LC1K, and relays CA2K, CA3K and CA4K. It is a front-mounting block, 30 by 38 by 35 mm.

The contacts have a rated operational voltage of 690 V AC and a thermal current of 10 A at 50 °C. The 5 mA / 17 V minimum matters for PLC inputs fed at 24 V.

The datasheet describes a front-mounting block with screw clamp terminals, 30 mm high, 38 mm wide and 35 mm deep, weighing 0.045 kg. Rated operational voltage is 690 V AC at 25 to 400 Hz, conventional thermal current is 10 A at 50 °C, and the associated fuse is 10 A gG up to 690 V. Rated making capacity is 110 A, with short-time ratings of 80 A for 1 s, 60 A for 500 ms and 110 A for 100 ms. Minimum switching is 5 mA at 17 V, and the non-overlap distance between NC and NO contacts is 0.5 mm.

Ordering checklist for the LA1KN20

• Two NO contacts only.
• Contactor or relay family must be LC1K or CA2K, CA3K, CA4K.
• Voltage and current of the signal within 690 V and 10 A.
• Check the ambient limit of 50 °C in the cabinet.
• If a four-contact version is needed, see the LA1KN40.

What two NO contacts do on a TeSys K contactor

One normally open contact is wired across the start button to hold the coil in after the button is released, which is the self-holding or latching function. The second can drive a run lamp, a PLC feedback input or a second holding branch.

Because both contacts are NO, the block gives no interlock function. For interlocks combine it with an NC block or use the mixed LA1KN13.

LA1KN contact block family compared with the LA1KN20

The five TeSys K references below differ only in the arrangement of contacts. The highlighted row is the page you are reading.

Typical use of the LA1KN20 in Oman and the GCC

Small three-phase motors for ventilation fans, exhaust, and shutter drives use self-held starters. In Gulf facilities these are often skid-mounted or inside weatherproof boxes with a high summer temperature, so the ambient rating is worth a check.

The block is also used to feed a feedback signal to building management systems from simple contactors.

Installing the LA1KN20

Seat the block on the front of the contactor, tighten the terminals to 1.3 N.m and check the auxiliary contacts close when the contactor is operated by hand using the test button of the contactor.

If the contacts are used as a self-hold, test that releasing the start button leaves the contactor in; if it drops, check the terminal numbers against the schematic.

Information to send with an RFQ for the LA1KN20

• Full reference and quantity required
• Contactor or relay model the block mounts on
• Contact arrangement needed (NO and NC count)
• Control voltage and load of each circuit
• Delivery location and timing

Documents and quotation

A datasheet for the LA1KN20 is attached on this page. It carries the electrical, mechanical and environmental data summarised above, so the figures can be checked against your drawings.

Send the part number, quantity and application and we will confirm availability and a quotation. Seven Star LLC is an independent supplier in Muscat and is not affiliated with the manufacturer.