Mitsubishi S-T10 Magnetic Contactor (MS-T Series) — 2026 Specs, ROI and Maintenance Guide

The Mitsubishi S-T10 magnetic contactor is the frame-10 entry in the MS-T series, built for reliable small-to-mid motor switching in modern IT/OT-connected production environments.Key specifications:- AC-3 rated operational current: 9 A- Conventional free-air thermal current: 20 A- AC-3 rated motor capacity: 4 kW at 200-240 V- Coil voltage: 100-127 V AC or 200-240 V AC, 50/60 Hz- Main poles / auxiliary contact: 3P + 1NO- Mounting: DIN rail or screwROI and TCO view:The compact DIN-rail footprint reduces panel space and wiring time, while the low coil burden cuts energy consumption across thousands of switching cycles. The 1NO auxiliary contact provides a dry-contact feedback signal to PLCs, SCADA systems and IIoT gateways, enabling cycle counting and early wear detection for predictive maintenance programs.Maintenance best practices:- Inspect contact surfaces every 6-12 months for pitting or discoloration.- Keep the contactor free of dust, moisture and oil mist.- Verify coil voltage stability to avoid chatter and contact welding.- Use the auxiliary contact for runtime data instead of adding external sensors.Upgrade path:For larger compressor, conveyor or 100 A-class motor circuits, the Mitsubishi S-T100 / ST100 AC220V contactor offers the same MS-T reliability in a higher-capacity frame, allowing standardization from frame 10 to frame 100 across the production line.