The SAMWHA EOCR-3DD-05-24 is a sophisticated microprocessor-based (MCU) electronic over current relay designed for the reliable protection of three-phase induction motors. Unlike conventional thermal overload relays, the EOCR-3DD series provides precise digital monitoring, wide adjustment ranges, and specific fault diagnostics.
This model features a 24V AC/DC control voltage, making it ideal for control panels with low voltage safety requirements or specific industrial power supplies.
Key Features & Benefits
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Digital Ammeter Display: The built-in digital LED display shows real-time current values on each phase (A, B, C), allowing operators to monitor load conditions instantly without external test equipment .
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Comprehensive Protection: It integrates five critical protection functions into one unit:
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Over Current: Protects against excessive thermal loading.
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Phase Loss: Detects wiring breaks (Trip within 4 seconds).
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Phase Reversal: Prevents motor damage from incorrect wiring (Trip within 0.1 seconds).
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Phase Unbalance: Protects against voltage variations (Trip within 8 seconds).
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Locked Rotor (Stall): Detects mechanical jams or starting failures .
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Trip Cause Display: In the event of a failure, the relay displays a specific error code (e.g., “OC” for Over Current, “Lb” for Phase Loss). This eliminates guesswork during troubleshooting, saving valuable downtime .
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Adjustable Trip Curves: Users can select between Definite and Inverse time characteristics via DIP switch (SW3), allowing perfect coordination with upstream circuit breakers .
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Remote Reset Capability: Supports manual reset on the unit or electrical remote reset for automated systems .
Technical Specifications
| Specification | Value |
|---|---|
| Brand | SAMWHA |
| Model | EOCR-3DD-05-24 |
| Type | Digital Electronic Over Current Relay |
| Control Voltage (V) | 24V AC/DC (50/60Hz) |
| Current Range (05 Frame) | 0.5 ~ 6A (Direct connection) |
| Extended Range | Up to 720A with external current transformers (CTs) |
| Output Contacts (O.L) | 2-SPST / 3A @ 250VAC |
| Output Contacts (A.L) | 1-SPST / 3A @ 250VAC |
| Start Time (D-Time) | 1 ~ 120 Seconds (Definite) / 0 ~ 120 Seconds (Inverse) |
| Trip Delay (O-Time) | 0.3 ~ 25 Seconds (Definite) / 1 ~ 30 Seconds (Inverse) |
| Mounting | 35mm DIN Rail or Surface Mount |
| Accuracy | Current: ±5% / Time: ±5% |
Applications
The SAMWHA EOCR-3DD-05-24 is suitable for a wide range of industrial motor control applications, including:
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Pumps & HVAC Systems
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Conveyor Belts & Crushers
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Compressors & Fans
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Material Handling Equipment
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Mining Machinery (due to low voltage 24V control safety)
