Overview
The Mitsubishi TH-K12 overload relay is a thermal overload protection device designed for use in three-phase motor starter assemblies. Rated for up to 600V AC with an adjustable current range of 1.0–1.6A, this relay provides automatic overload and phase failure protection to prevent motor damage from sustained overcurrent conditions. Equipped with 1A+1B (1NO+1NC) auxiliary contacts, the TH-K12 is a compact, reliable component manufactured by Mitsubishi Electric Corp., a trusted name in industrial automation.
Key Features
- 600VAC Rated Voltage: Suitable for standard three-phase industrial systems
- Adjustable Current Range: 1.7-2.5A full-load amp setting with 125% trip sensitivity
- Auxiliary Contacts: 1 NO + 1 NC (95-96 / 97-98 terminals) for signaling and alarm circuits
- Three-Pole Design: Pole configuration for three-phase motor protection with phase failure detection
- Direct Contactor Mount: Mounts directly to compatible Mitsubishi contactors or DIN-rail with adapter
- Manual/Automatic Reset: Manual and automatic reset mode options
Technical Specifications
- Rated Voltage: 600VAC (AC)
- Current Range: 1.7–2.5A adjustable
- Trip Setting: 125% of full-load amps
- Poles: 3 (three-phase)
- Auxiliary Contacts: 1NO + 1NC
- Contact Rating: Per IEC standards
- Standards Compliance: IEC292-1, 660V~
- Weight: 100–110 g
- Mounting: Direct or DIN-rail adapter
- Manufacturer: Mitsubishi Electric Corp., Japan
- Reset Mode: Manual/automatic selectable
Typical Applications
- Motor Starters: Typically used in conjunction with contactors in motor starter assemblies
- Pump & Fan Motors: Soft-start and reversing starter circuits
- Conveyor Systems: Overload and jam protection for continuous-duty loads
- HVAC Equipment: Pump controls, HVAC systems, and conveyor motor protection
- Industrial Automation: General industrial automation requiring motor overload protection
- Control Panels: OEM panel builder integration for standard three-phase motor circuits
Compatibility & Replacements
Compatible With
- Mitsubishi S-K10, S-K12, S-KR11 contactors
- Three-phase AC induction motors (squirrel-cage)
- Standard 600VAC three-phase power systems
- DIN-rail mounting systems (with optional adapter)
- Motor control centers (MCCs) and industrial panel assemblies
Replaces / Drop-In Replacement For
- Mitsubishi TH-K12 thermal overload relay (all standard variants)
- Mitsubishi TH-K12AB, TH-K12KP variants with same 600VAC/1.7-2.5A rating
- Mitsubishi TH-N12 series (verify current range compatibility)
Works With
- Mitsubishi contactors (S-K, S-KR series)
- IEC 60947 standard three-phase motor starters
- Thermal overload relay circuits (no software/programming required)
- Manual and semi-automatic motor starter control schemes
- Auxiliary relay logic chains (via 1NO+1NC contacts)
