Mitsubishi SD-Q12 Contactor — 4-Pole 12 A Industrial Control Relay

MS-N Series Contactor · DIN-Rail Mount · 4 × Normally-Open Main Poles

The Mitsubishi SD-Q12 is a 4-pole AC contactor rated at 12 A (AC-1 / resistive duty) and built on Mitsubishi Electric's MS-N platform — the same family that includes the S-N10 / S-N12 / S-N20 power contactors. The "Q" in the part number indicates the 4-pole "auxiliary" configuration: 4 main poles that are all normally-open (4a), so the SD-Q12 is typically used as a control relay inside motor-starter assemblies, lighting panels, HVAC control cabinets, and PLC I/O interposing relays where a higher inrush than the PLC output can handle needs to be switched by a coil-driven contact block.

At koeed.com we list the SD-Q12 as a control-cabinet contactor / relay. It is most often used in two roles: (a) a 24 VDC or 100/200 VAC coil interposing relay between a PLC digital output and a higher-current load (solenoid valve, contactor coil, signal lamp), and (b) a four-circuit lighting or heater contactor in HVAC and panel-building applications where DIN-rail space is at a premium.

Key Specifications

Datasheet Highlights

• 4-pole 4a configuration in a single DIN-3 module footprint, ideal for lighting control and HVAC interlock circuits where a standard 3-pole contactor is the wrong shape.
• 12 A AC-1 thermal current covers resistive heater banks, small motor loads, and solenoid-valve banks at 200 / 220 / 380 / 440 VAC.
• Coil is available in 24 VDC, 100/110 VAC, and 200/220 VAC variants — the correct coil must be ordered against the PLC output voltage and panel control power.
• Mechanically compatible with MS-N family accessories (auxiliary contact blocks, mechanical interlocks, surge suppressors) so the same spare fits a wide range of starter assemblies.
• 10 M mechanical operations and 500 k electrical operations at AC-1 are well above the typical duty on a relay-output PLC interposing channel.
• Finger-safe IP2X terminals reduce cabinet-build labour and meet IEC 61439-1 panel-builder safety requirements.

Typical Applications

• PLC interposing relay: between a MELSEC, Allen-Bradley, or Siemens relay output and a higher-current load (heater, solenoid, signal lamp) where the PLC output rating is exceeded.
• Lighting control panel: 4-pole 4a layout matches the four circuits of a small commercial / industrial lighting panel; the SD-Q12 is mounted next to a Mitsubishi NO-10C timer or a Keyence LV-N sensor.
• HVAC control cabinet: 4-pole contactor for chiller enable, condenser fan, hot-gas bypass, and electric reheat — wired from a Schneider or Mitsubishi HVAC controller.
• Pump & valve manifolds: 24 VDC coil version is used to gang four 24 VDC solenoid valves from a single PLC output bank in a water-treatment skid.
• Motor-reversing / star-delta starter: SD-Q12 as the star-point contactor in a star-delta starter, where 4 poles are needed to short the motor windings during the start sequence.
• Capacitor-bank switching: 4-pole layout for switching power-factor correction stages, with pre-charge resistors in series for inrush limiting.

Related Modules & Cross-Reference

A contactor swap is usually part of a wider cabinet refurbishment. KOEED can ship the SD-Q12 with a matched Mitsubishi coil, surge suppressor, and a wider control-cabinet kit:

Browse the KOEED contactors & relays and Mitsubishi Electric collections to bundle a full cabinet-build kit.

Warranty & Authenticity

Each SD-Q12 is supplied as a brand-new, factory-sealed Mitsubishi Electric contactor with lot code and date code recorded for full traceability. KOEED sources from authorised Japanese and EU distribution channels, and counterfeits are rejected at incoming inspection. A 12-month limited warranty covers manufacturing defects, and KOEED handles return shipping and replacement from EU/US stock at no charge.

Cross-reference: SD-Q12 · SDQ12 · Mitsubishi MS-N 4-pole contactor · 12 A control relay · B2B industrial automation spares. KOEED Automation — independent distributor of industrial automation spare parts, including Allen-Bradley, Siemens, Mitsubishi, Omron, Schneider Electric, FANUC, Yaskawa, Panasonic, and Keyence.