Overview
The Square D LRD3355 is a TeSys Deca differential thermal overload relay engineered for industrial motor protection in demanding applications. This 3-pole overload relay detects overcurrents in motor lines and works with TeSys D contactors to form a complete motor starter, disconnecting power before damage occurs to motor windings.
Key Features
- Adjustable trip current rating: 30-40 amperes
- Class 10A calibration for fast, reliable tripping
- Differential thermal overload detection with single-phase sensitivity
- Manual or automatic reset selectable via dial
- Bi-metallic ambient compensated design
- Screw terminal connections for secure installation
- Multi-standard certified (IEC, UL, CSA, CCC, EAC, ATEX, Marine)
- RoHS/REACH compliant
Technical Specifications
- Current Range: 30-40 amperes adjustable
- Trip Class: Class 10A
- Protection Type: Differential thermal overload
- Poles: 3-pole
- Auxiliary Contacts: 1 NC, 1 NO
- Reset Options: Manual or Automatic (field selectable)
- Terminal Type: Screw clamp
- Mounting: DIN rail compatible
Typical Applications
The LRD3355 is ideal for three-phase motors up to 25 HP, providing protection in:
- Machine tools and industrial automation
- HVAC systems and mechanical equipment
- Manufacturing conveyor systems
- Pump and fan motor starters
- General industrial motor control
Compatibility & Replacements
Compatible With
- TeSys D contactors (LC1D80 and LC1D95 models)
- Standard motor starter assemblies
- IEC 60947-4-1 compliant control systems
- Three-phase industrial electrical networks
Replaces / Drop-In Replacement For
The Square D LRD3355 is a direct replacement for earlier TeSys LRD thermal overload relays in the same current class. Verify compatibility with your system integrator for older motor starter assemblies.
Works With
- TeSys Deca motor starter systems
- Standard industrial three-phase networks
- IEC and NEMA-rated motor control panels
- Contactor-based motor protection schemes
