Overview
The Cerus Industrial CTK-40 12-18A is a thermal overload relay engineered to protect three-phase motors and electrical equipment from sustained overcurrent conditions. This differential type relay with Class 10 protection characteristics delivers precise and repeatable thermal response, making it suitable for controlling motor starters in industrial automation, manufacturing, and control systems. As a surplus new-in-box unit, it offers cost-effective protection without the premium of original stock.
Key Features
- Differential type thermal overload relay—ensures reliable trip accuracy
- Class 10 protection—complies with standard thermal overload relay classifications
- Rated current range: 12–18 Amps—covers common small to mid-range motor protection
- Three-phase motor control compatible—standard installation in NEMA starter enclosures
- Tested and fully functional—new in factory box condition
Technical Specifications
| Rated Current Range | 12–18 Amps (adjustable within range) |
| Relay Type | Differential Thermal Overload |
| Protection Class | Class 10 |
| Phase | Three-Phase |
| Manufacturer | Cerus Industrial (Franklin Electric) |
| Part Number | CTK-40 |
| Status | Discontinued by manufacturer; available as new surplus |
| Condition | New in Box |
| Weight | Approximately 0.45 lbs |
Typical Applications
- Three-phase motor protection in NEMA starters
- Machine tool and industrial machinery motor control
- Pump and compressor motor protection
- Conveyor and material handling equipment
- Industrial automation and process control systems
Compatibility & Replacements
Compatible With
- NEMA-type motor starters and contactors
- Three-phase squirrel-cage and wound-rotor motors
- Industrial control panels and enclosures rated for thermal overload relays
- Franklin Electric and Cerus Orion control products
Replaces / Drop-In Replacement For
- Cerus CTK-40 series overload relays in the 12–18A range
- Legacy Cerus Orion thermal overload relays
- Other Class 10 differential-type thermal overload relays with 12–18A ratings—verify terminal compatibility before installation
Works With
- Magnetic motor starters and soft starters
- AC magnetic contactors (50/60 Hz)
- Traditional hardwired motor control circuits
- NEMA enclosure-based automation systems
