Best 3 Phase Overload Relay Guide: Top 5 Picks for Motor Protection
The right 3 phase overload relay protects motors in HVAC, pumps, compressors, and industrial equipment from overloads, phase loss, and unbalance conditions. This guide highlights five reliable options, comparing features, mounting styles, and reset options to help you choose the best fit for your system. Each product below is selected for American applications, compatibility with standard HVAC and industrial controls, and clear operating configurations.
Summary at a glance
| Product | Brand | Key Use | Typical Amp Range | Reset Type |
|---|---|---|---|---|
| DPER07 Easy TeSys Thermal Overload Relay | Schneider Electric | HVAC, compressors, pumps | 1.6–2.5 A | Manual/Automatic |
| NR2-93 3 Phase Thermal Overload Relay | Walfront | Motor protection, phase break safeguard | 40 A | Automatic |
| NR2-36 23-32A Thermal Overload Relay (2-Pack) | Walfront | 3-phase motor protection | 23–32 A | Automatic/Manual options |
| DPER03 Easy TeSys Thermal Overload Relay | Schneider Electric | HVAC, pumps, compressors | 0.25–0.4 A | Manual/Automatic |
| LR2 JR28-25 2.5A 3-Phase Relay | Generic | Motor protection | 2.5 A | Automatic |
Schneider Electric DPER07 Easy TeSys Thermal Overload Relay
This thermal overload relay is designed for network frequencies of 0–4000 Hz, with insulation ratings up to 600V UL/cUL and 690V IEC. It features a tripping class 10 setting, making it suitable for protecting 3-phase motors in HVAC systems, elevators, pumps, compressors, and agricultural applications. The DPER07 has a compact, modular design ideal for space-constrained panels and can be configured quickly to meet specific needs. It provides reliable protection against overloads, phase failures, and phase unbalances, while its durable construction guards against dust and other environmental elements.
Key considerations
- Compact modular design fits tight control enclosures.
- Wide network frequency compatibility supports varied motor controls.
- Reset options allow manual or automatic restoration after a fault.
Walfront NR2-93 3 Phase Thermal Overload Relay
Designed for automatic operation, the NR2-93 supports voltages up to 690V and is suitable for 50–60 Hz motor circuits. It provides protection for motors against overload conditions and helps prevent damage caused by phase imbalance or abandonment. It is commonly used to protect industrial motors in systems where automatic reset is preferred to maintain uptime without operator intervention.
Key considerations
- Automatic reset reduces manual intervention in continuous-run environments.
- Higher current rating broadens suitability for larger motors.
- Good option where simple, dependable phase protection is needed.
Walfront NR2-36 23-32A Thermal Overload Relay (2-Pack)
This two-pack of Walfront NR2-36 relays provides durable, high-quality protection for 3-phase motors with insulation ratings up to 690V, suitable for 50–60 Hz circuits. The mechanism includes automatic and manual reset options, plus trip indication, stop, and test controls for straightforward operation. It is designed to offer precise protection against phase breaks and motor overloads, supporting reliable everyday use in industrial settings.
Key considerations
- Two-relay pack offers cost-effective redundancy for critical systems.
- Voltage rating supports a wide range of motor sizes and configurations.
- Trip indicators and test features aid maintenance and fault diagnosis.
Voltage Phase Sequence Protector 3-Phase Monitor
This monitor provides universal compatibility for 3-phase voltage protection ranging from 208 to 480V, with a universal modular structure and 35mm rail mounting. It supports automatic or manual resets and allows adjustment of overvoltage, undervoltage, unbalance values, and action times. This flexibility makes it suitable for machine tools and other equipment requiring precise voltage guardrails across varied international standards.
Key considerations
- Wide voltage range supports global applications.
- Adjustable protection thresholds enable fine-tuning for different motors.
- Rail-mounted design simplifies panel integration.
Schneider Electric DPER03 Easy TeSys Thermal Overload Relay
The DPER03 shares the same TeSys design ethos as the DPER07, offering 0.25–0.4 A protection for small 3-phase motors in HVAC, elevators, pumps, and compressors. Its compact, modular layout makes it ideal for compact control panels while providing reliable protection against overloads, phase failures, and unbalances. Its rugged construction helps resist dust and environmental exposure in typical mechanical rooms.
Key considerations
- Small-branch-motor protection requires a compact relay with solid protection features.
- Compatibility with manual/automatic reset provides flexible maintenance modes.
- Durable build suited for challenging environments.
LR2 D13 8A 5.5-8A 3 Phase Overload Relay
Designed for 3-phase motors with a range around 8A, the LR2 D13 provides a dependable motor protection solution. It is a robust option for traditional control panels and is designed to handle typical industrial loads, helping to prevent motor damage due to overloads, phase loss, and unbalance. The unit’s construction aims for long service life in standard workshop and shop-floor environments.
Key considerations
- Solid protection for mid-range motor currents.
- Simple integration with existing 3-phase control circuits.
- Manual/automatic options available on select models.
LR2 JR28-25 2.5A 3-Phase Overload Relay
The JR28-25 variant covers 2.5A in three-phase circuits with a 1NO/1NC contact arrangement. It provides essential protection for motors and is suitable where straightforward electrical protection is needed without advanced diagnostics. It complements a broad range of general-purpose motor control configurations and is easy to mount within standard control panels.
Key considerations
- Appropriate for smaller to mid-size motors.
- 1NO/1NC configuration supports simple stop/start control.
- Compact form factor eases panel integration.
Buying Guide: Key Purchase Considerations
When selecting a 3 phase overload relay, consider motor current and protection needs, voltage and frequency compatibility, reset behavior, and panel space. Below are factors to help you compare options objectively.
- Current rating vs. motor nameplate: Choose a relay with a current range that safely surrounds your motor’s running current and startup surge.
- Voltage ratings and insulation: Ensure the relay supports your system voltage (often 208–480V or up to 690V) and has appropriate insulation standards for your environment.
- Reset type: Manual resets are common in systems requiring operator acknowledgement after a fault; automatic resets favor uptime in unmanned or high-availability applications.
- Protection features: Look for phase loss, phase unbalance, and overload protections, plus trip indicators for quick fault diagnosis.
- Mounting and enclosure fit: Rail- or panel-mount options should align with your control cabinet space and wiring accessibility.
- Maintenance and diagnostics: Models with clear trip indication and test/Button features simplify preventive maintenance.
- Brand and compatibility: Established brands (Schneider Electric, Walfront) offer broader spare parts support and documented integration with common PLCs and contactors.
- Cost vs. redundancy: For critical motors, consider a second relay or a dual-Relay arrangement to maintain protection if one unit fails.
Selecting the correct 3 phase overload relay involves balancing current needs, voltage compatibility, and maintenance requirements. The five options highlighted here provide a spectrum from compact, HVAC-focused relays to larger, higher-current protections suitable for industrial motors. Use the buying guide to map your specific motor characteristics to a relay’s capabilities, ensuring reliable motor protection and minimal downtime.