Schneider Electric CA2KN22U7 TeSys K Relay 2NO+2NC 230-240 V AC

CA2KN22U7: control relay with 2 NO + 2 NC and a 230-240 V coil

The CA2KN22U7 is a Schneider Electric TeSys K control relay listed in the datasheet as: TeSys K control relay – 2 NO + 2 NC – <= 690 V – 230 to 240 V AC coil. A 2 NO + 2 NC contact set is the most flexible arrangement of the CA2K range: two circuits that close on energising and two that open. That mix lets one relay both permit and block, which is why it appears in interlocks, in latching and seal-in circuits and in logic that needs a defined fail state. Seven Star LLC supplies the CA2KN22U7 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 two normally open and two normally closed contacts, the coil is 230-240 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 CA2KN22U7

Contact set and operation of the CA2KN22U7

In a seal-in (self-holding) circuit one NO contact bridges the start button, while an NC contact in series with the stop path drops the circuit when another function demands it. With the coil off the two NC contacts are closed, so a signal such as ‘not running’ or ‘permissive healthy’ is available without any extra wiring.

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 CA2KN22U7

The 230 to 240 V AC coil covers the upper end of the mains range and suits networks whose single-phase voltage runs close to 240 V. It is the version to pick when the actual control voltage at site is measured above 230 V.

The datasheet lists the coil voltage as 230 to 240 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 CA2KN22U7: 1.3 W. Immunity to micro-breaks: 2 ms.

Its contact data are identical to those of the other CA2K 2 NO + 2 NC reference, so only the coil changes.

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 CA2KN22U7

The CA2KN22P7 differs in coil 230 V AC 50/60 Hz against 230 to 240 V AC 50/60 Hz here. The CA2KN31B7 differs in contacts 3 NO + 1 NC against 2 NO + 2 NC here; coil 24 V AC 50/60 Hz against 230 to 240 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 CA2KN22U7

Selection tip for the CA2KN22U7: the U7 coil covers 230 to 240 V, a range that is higher than the single 230 V of the P7 version. Pick it when a site reading shows the control voltage regularly above 235 V, because a coil that runs near the top of its operating window carries more current and heats more than one chosen for the actual supply. With two NO and two NC contacts it is also a practical standby for interlocking relays in air-conditioning plant panels, where the same coil voltage is shared by contactors and timers.

• Count the NO and NC contacts of the circuit diagram; this reference gives exactly two of each.
• If a fourth NO is needed with no NC, the 4 NO reference is simpler.
• Coil voltage: 230-240 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 CA2KN22U7

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 CA2KN22U7 is used in Oman and the GCC

Choose this reference for panels where the supply measured at the coil sits close to 240 V, for example next to the transformer or in a building with a high set tap. A coil that is rated for the real voltage runs cooler and lasts longer, which matters in warm plant rooms.

As a spare, the CA2KN22U7 is also a candidate to replace a CA2KN22P7 in a 230 V panel, since the datasheet coil ranges overlap at 230 V; the relay must be checked against the real voltage and the 0.8 to 1.15 operating window before the substitution.

Information to send with an RFQ for the CA2KN22U7

• Full reference (CA2KN22U7) 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 CA2KN22U7 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.