Schneider Electric CA2KN31M7 TeSys K Relay 3NO+1NC 220-230 V AC

CA2KN31M7: control relay with 3 NO and 1 NC contact and a 220-230 V coil

The CA2KN31M7 is a Schneider Electric TeSys K control relay listed in the datasheet as: TeSys K control relay – 3 NO + 1 NC – <= 690 V – 220 to 230 V AC coil. A 3 NO + 1 NC set suits circuits where most functions are ‘make on energise’ but one signal must be the opposite, for example a seal-in contact, two output contacts and one fault or feedback contact that is closed when the relay is off. Seven Star LLC supplies the CA2KN31M7 in Oman and the GCC as an independent supplier based in Muscat.

The datasheet gives the device short name CA2K and the application as control circuit. The contact set is three normally open and one normally closed contact, the coil is 220-230 V AC 50/60 Hz, and the utilisation categories are AC-15 and DC-13, the standard categories for control-circuit loads such as contactor coils and signal lamps.

Technical specifications of the CA2KN31M7

Contact set and operation of the CA2KN31M7

Three NO contacts can carry the seal-in, the output command and a feedback signal at the same time, while the single NC contact gives an ‘off’ indication or a permissive that falls away when the coil pulls in. The datasheet lists a non-overlap distance between NO and NC contacts, which matters when the NC contact feeds a logic input that must not see both states together.

Operating times in the datasheet: 10 to 20 ms coil de-energisation and NO opening; 10 to 20 ms coil energisation and NO closing; 15 to 25 ms coil de-energisation and NC closing; 5 to 15 ms coil energisation and NC opening. Non-overlap distance between NO and NC contacts: 0.5 mm. Mechanical durability: 10 Mcycles. Maximum operating rate: 10000 cyc/h.

Coil supply, contact ratings and low-level switching of the CA2KN31M7

The 220 to 230 V AC coil covers the lower end of the mains range and suits panels where the control supply is a single phase of a 220 V network or a 230 V supply with a negative tolerance. It is usually chosen for panels in which push-buttons and lamps are already wired at mains level.

The datasheet lists the coil voltage as 220 to 230 V AC 50/60 Hz. Operating limits: Drop-out: 0.2 to 0.75 Uc (at <50 °C); Operational: 0.8 to 1.15 Uc (at <50 °C). Inrush consumption: 30 VA (at 20 °C). Hold-in consumption: 4.5 VA (at 20 °C). Heat dissipation of the CA2KN31M7: 1.3 W. Immunity to micro-breaks: 2 ms.

The three NO and one NC arrangement matches the wiring of many earlier start-stop panels where one NO seals in, one drives the contactor and one signals the state.

Conventional free-air thermal current: 10 A (at 50 °C). Rated making capacity: 110 A conforming to IEC 60947. Associated short-circuit protection: 10 A gG conforming to IEC 60947; 10 A gG conforming to VDE 0660. Minimum switching voltage: 17 V. Minimum switching current: 5 mA. Insulation resistance: > 10 MOhm. Rated operational voltage: <= 690 V <= 400 Hz.

Low-level circuits deserve a check of the datasheet minimums. A contact that has carried a heavy mains load develops a film that can block a very small signal current, so a relay used for a milliamp PLC signal should not also be used for a heavy load. Keeping signal duty and power duty on separate relays avoids intermittent faults that are hard to trace.

Family comparison for the CA2KN31M7

The CA2KN31B7 differs in coil 24 V AC 50/60 Hz against 220 to 230 V AC 50/60 Hz here. The CA2KN31U7 differs in coil 230 to 240 V AC 50/60 Hz against 220 to 230 V AC 50/60 Hz here.

The table lists the CA2K references of this group; contact set and coil are the only things that change, and the body, size and ratings are shared.

Selection checklist for the CA2KN31M7

Selection tip for the CA2KN31M7: the M7 version covers 220 to 230 V and is the relay to check first when a panel was built for a 220 V network. Compare it with the 230 to 240 V U7 version before ordering for a site whose voltage sits near 230 V, because both ranges include that value. With three NO contacts and one NC, it replaces many older start-stop relays without any rewiring of the control diagram, as long as the NC contact was used for the same purpose in the original.

• Check that one NC contact is enough; otherwise use the 2 NO + 2 NC reference.
• Verify which terminal is the NC contact on the front; the terminal numbers are printed beside each screw.
• Coil voltage: 220-230 V AC 50/60 Hz; operating limits 0.8 to 1.15 times the rated voltage.
• Mounting: rail or plate, body 45 mm wide x 58 mm high x 57 mm deep.
• Short-circuit protection: use the associated 10 A gG fuse noted in the datasheet.

Mounting, wiring and environment for the CA2KN31M7

The relay mounts on a rail or on a plate, measures 45 mm wide x 58 mm high x 57 mm deep and weighs 0.18 kg. Terminals are screw clamps; the datasheet gives 1.3 N.m – on screw clamp terminals – with screwdriver flat Ø 6 mm, and accepted conductors from 0.34 to 4 mm squared depending on type and number. Use a ferrule on flexible conductors and re-tighten the screws after the first thermal cycles, because screw clamps settle when copper creeps under load; mark the torque on the panel record.

The environment is stated as -25 to 50 °C in operation and -50 to 80 °C in storage, an altitude of 2000 m without derating, protection IP2X and a flame retardance of V1 to UL 94. The mechanical robustness data in the datasheet give vibration and shock withstand figures for both the open and closed state, which is useful for relays on moving or shaking machines.

Where the CA2KN31M7 is used in Oman and the GCC

This version is selected where the control circuit is a single-phase 220 or 230 V supply, as in older switchgear and in imported machines built for 220 V networks. It is a straightforward spare for relays of the same type found in existing panels.

When a relay is replaced in an existing panel, compare the printed coil voltage on the old relay with the datasheet: 220 to 230 V AC 50/60 Hz here. A relay with a different coil range should always be checked against the datasheet operating window of 0.8 to 1.15 times the rated coil voltage.

Information to send with an RFQ for the CA2KN31M7

• Full reference (CA2KN31M7) and quantity required
• Supply and control voltage at site, with the frequency
• Existing panel, rail and neighbouring devices it must fit beside
• Delivery location and timing
• Whether it is a spare, a like-for-like replacement or a new installation
• Contact set needed: number of NO and NC contacts

Documents and quotation

A datasheet for the CA2KN31M7 is attached on this page. It lists the electrical, mechanical and environmental data summarised above, and it should be read together with the manufacturer’s installation instructions for the final design.

Send us 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.