Phoenix Contact REL-MR-24DC/21-21 Plug-in Relay 2 CO

REL-MR-24DC/21-21: plug-in miniature relay, 24 V DC coil, 2 changeover contacts

The Phoenix Contact REL-MR-24DC/21-21 (order no. 2961192) has two changeover contacts and a 24 V DC coil in a 12.7 mm wide, 29 mm high, 15.7 mm deep housing. The contacts are AgNi, and the continuous limit is 8 A at up to 250 V AC/DC. The input voltage range is 15.6 to 59.52 V DC.

Seven Star LLC supplies the REL-MR-24DC/21-21 as an independent supplier in Muscat for projects in Oman and the GCC, quoted against the exact part number shown here.

Technical specifications of the REL-MR-24DC/21-21

How the REL-MR-24DC/21-21 works

The REL-MR-24DC/21-21 is a plug-in miniature power relay: a coil that attracts an armature and moves one or two changeover contacts. When the coil is energised within the input range in the table, the common terminal changes from the normally closed to the normally open contact. The coil and the contacts are isolated from each other, with the winding/contact test voltage shown in the table, so a low-voltage control signal can switch a mains-level load. The relay has no socket of its own and is designed to be plugged into a compatible base, for instance a socket module.

Coil resistance is 1440 ohms with a typical 17 mA current. Response time is 7 ms and release 3 ms. Mechanical life is 3 x 10^7 cycles. At 24 V DC the interrupting rating is 192 W, and the UL motor load is 1/4 HP at 120 V AC.

Where the REL-MR-24DC/21-21 fits in a system

REL-MR relays are the replaceable switching element in many Phoenix Contact relay modules and in customer-built relay sockets. Ordering the relay alone is typical for spares or when a socket is already fitted. Family members differ by coil voltage, number of contacts, contact material and current rating, so the part number decides compatibility with the socket in your panel. Always check that the relay fits the socket series installed.

The REL-MR-24DC/21-21 suits two-circuit switching from one coil, for example a power contact plus a feedback contact. If you need a larger single contact current, the HC version 2961312 has 16 A.

Selection and ordering checklist

• Confirm the coil voltage of the REL-MR-24DC/21-21 against the control signal and its tolerance.
• Check the number of changeover contacts and the pin pattern of the socket.
• Check the load current and inrush against the contact data in the table.
• Use gold-plated contacts only for low-level signals, and power contacts for loads.
• Confirm the dimensions fit the socket and the DIN-rail space.
• Verify the ambient temperature.

Installation, commissioning and maintenance of the REL-MR-24DC/21-21

Plug the REL-MR-24DC/21-21 firmly into a compatible socket, never into a socket designed for a different coil voltage. Check that the relay latches mechanically or sits fully in the retaining clip. Observe the mounting position: the datasheet permits any position. Replace the relay as a whole; do not attempt to clean or open it.

The test voltages are 5 kV between coil and contacts, 2.5 kV between contacts and 1 kV across an open contact. Keep these in mind when wiring different voltage levels to the two contacts.

Typical applications in Oman and the GCC

In Oman and the GCC, plug-in relays are used in pump and valve controls, compressor panels, HVAC and lighting control and as spare parts in maintenance stores. Keeping a few spare relays per coil voltage shortens repair times considerably.

Two-contact relays are widespread in motor starters, damper actuators and signalling panels in GCC industrial and building installations.

Comparison with related REL-MR plug-in relays

Information to send with an RFQ

• Full part number REL-MR-24DC/21-21 and quantity.
• Socket or relay module in which it will be used.
• Coil voltage and load details.
• Operating temperature and duty.
• Delivery location and date.

Documents and quotation

Send us the part number REL-MR-24DC/21-21 and the quantity you need, and we will confirm which official documents are available for this device. Seven Star LLC is an independent supplier in Muscat and quotes for projects across Oman and the GCC; we do not act on behalf of the manufacturer.

Please also tell us the delivery location and required timeline so that availability can be checked before you commit to a project schedule.