Best Three-Phase Motor Overload Protection Solutions for Industrial Motors
Three-phase motors require reliable overload protection to prevent damage from overloads, phase loss, and electrical faults. This guide highlights top-rated overload relays designed for 5.5–8 A ranges and compatible contactors, offering adjustable settings, manual or auto reset, and phase-failure protection. Compare features, mounting options, and compatibility to choose a device that fits your motor size and control panel layout. The selections below emphasize broad voltage compatibility (up to 690V), robust trip classifications, and easy integration with common CJX and LC1D/LR series contactors.
Choosing the right thermal overload relay helps keep downtime to a minimum and extends motor life. The table below provides a quick overview of five representative products and their key attributes. This snapshot can guide deeper reading on each model’s compatibility with your starter assemblies and control panels.
| Product | Brand | Voltage Range | Current Range | Key Feature |
|---|---|---|---|---|
| JR28-25 5.5-8A Thermal Overload Relay | Kwaich | 690V | 5.5–8 A | 1NO 1NC, auto/manual reset, phase protection |
| Thermal Overload Relay 23-32A | Walfront | 690V | 23–32 A | Phase loss and overload protection |
| NR2-25 Thermal Overload Relay | PETiB | 690V | 0.1–25 A | Phase loss protection with adjustable ranges |
| LR2 D13 8A 5.5-8A Relay | Generic | 690V | 5.5–8 A | 1NO 1NC, compatible with JR28-25 family |
| SHAUNI RHN-10K | SHAUNI | Ui 600V | 10 A | 1NO 1NC, 3-phase protection |
JR28-25 5.5-8A Thermal Overload Relay, 3 Phase Protection
The JR28-25 is a 5.5-8 A adjustable thermal overload relay designed for three-phase motors up to 690V. It features a 1NO + 1NC auxiliary contact, manual or automatic reset, and a visible trip indicator. The device supports phase-failure and over-current protection, ideal for motor starter assemblies and DIN-rail installations. It is compatible with CJX2-D09, LC1D09-LC1D18, and LR2-D13 contactors when selecting matching frame sizes and terminal configurations, ensuring versatile integration in IEC-based starters.
Walfront Thermal Overload Relay 23-32A
Walfront’s 23-32A thermal overload relay provides robust phase loss and overload protection with automatic and manual reset options. Its 690V insulation rating suits a variety of three-phase motor circuits, offering reliable trip logic and a clear trip indication. The device also includes a test function for commissioning and maintenance, making it suitable for control panels and motor control centers where dependable protection is essential.
NR2-25 Thermal Overload Relay
NR2-25 offers a broad 0.1–25 A adjustable current range and 690V insulation rating. It integrates phase loss protection with compensation technology to maintain stable motor performance across temperature variations from -35°C to +70°C. Designed for CJX2 contactors (CJX2-09 to CJX2-32), it reduces wiring complexity and supports reliable operation in diverse industrial environments.
LR2 D13 8A 5.5-8A Relay
The LR2 D13 relay provides 5.5–8 A protection for 3-phase motors, featuring a 1NO 1NC contact configuration and compatibility with JR28-25 modules. Its compact design makes it a practical choice for motor starter panels, mounting beneath compatible contactors, and easy integration into existing CJX2 or LC1D-based systems. Verify contactor frame size and auxiliary configuration for optimal pairing.
SHAUNI RHN-10K Thermal Overload Relay
SHAUNI’s RHN-10K unit is a three-phase thermal overload relay with 1NO 1NC contacts and a Ui rating of 600V. It includes standard overload protection features and is suitable for integration into common motor starter configurations. This model emphasizes durability and reliable trip behavior in compact IEC-based motor control panels, making it a practical option for routine motor protection tasks.
JR28-25 (4–6A) Thermal Overload Relay
This variant of the JR28-25 covers 4–6 A with 3-pole protection and an auto/manual reset option. It is designed for direct mounting under CJX2 or LC1D series contactors and is compatible with LR2-D13 frames. Features include a 690V insulation rating, trip indicator, and a test button for quick verification during commissioning and maintenance. Ensure motor full-load current aligns with the 4–6 A setting for proper protection.
Buying Guide: Key Considerations for Selecting a 3-Phase Motor Overload Relay
- Current setting range: Match the relay’s adjustable range to the motor’s full-load current (FLC). A narrow range may require a different model or a dedicated current insert.
- Voltage rating: Ensure insulation and operating voltage align with your system (commonly up to 690V for industrial motors).
- Protection features: Look for phase loss/phase failure protection, overload protection, and phase-reversal handling if applicable to your installation.
- Auxiliary contacts: Decide if 1NO/1NC is enough or if additional contacts are needed for interlocking or signaling in your control circuit.
- Reset options: Manual vs. automatic reset impact restart logic and safety; consider how easily technicians can verify and reset faults.
- Mounting and compatibility: Confirm mounting style (DIN-rail, panel, or under-contactor) and verify compatibility with CJX2, LC1D, LR-series contactors in your starter assembly.
- Enclosure and protection rating: IP ratings and protective covers reduce contact risk and suit harsh environments.
- Diagnostics: Visible trip indicators, test buttons, and reset controls speed commissioning and troubleshooting.
- Environmental range: Temperature tolerance and stability at ambient conditions influence long-term reliability in factories or outdoors.
- Maintenance and serviceability: Availability of spare parts, cross-reference to common catalogs, and ease of wiring streamline future service.
When selecting a 3-phase motor overload relay, balance current accuracy, protection scope, and ease of integration with your existing motor starters. Cross-reference with your contactor frames (D09–D32, LR2, LC1D, etc.) to confirm compatibility and avoid misfits in panel layouts. Consider maintaining an inventory of a few common settings to expedite replacement during preventive maintenance.