Why Choose the ABB RD3M-48 Residual Current Relay?
The ABB RD3M-48 is a DIN-rail mounted electronic Type A residual current relay designed to provide residual current protection and earth leakage monitoring in industrial low-voltage installations. As part of ABB’s Earth Monitoring Devices range, it operates with an external ABB TR-series toroidal transformer and can be combined with suitable circuit-breaking equipment to create a complete residual current protection system.
The RD3M-48 provides adjustable sensitivity and operating time together with a 60% pre-alarm threshold and frequency filtering. The frequency filter helps the relay operate reliably in installations containing electronic equipment and other loads capable of producing higher-frequency leakage components, while the pre-alarm function enables developing leakage conditions to be identified before the main trip threshold is reached.
Designed for a 12–48 V AC/DC operating voltage, the RD3M-48 is particularly suitable for industrial control systems using low-voltage auxiliary supplies. Its compact three-module DIN-rail format allows straightforward installation within distribution boards and control panels alongside ABB S200 miniature circuit breakers and compatible Tmax moulded-case circuit breakers.
Key Advantages
- Electronic Type A residual current monitoring for industrial electrical installations.
- 12–48 V AC/DC operating voltage suitable for low-voltage control systems.
- 60% pre-alarm threshold provides early indication of developing residual current conditions.
- Frequency filter supports dependable monitoring in electrically demanding installations.
- Adjustable sensitivity and 0–10 s operating delay support protection coordination.
- Compact three-module DIN-rail mounting simplifies integration into electrical panels.
Key Features
- ABB RD3 electronic residual current relay series.
- Type A residual current characteristic.
- 12–48 V AC/DC rated operational voltage.
- 48 V AC/DC rated control supply voltage.
- 50–60 Hz rated frequency.
- 60% pre-alarm threshold.
- Frequency filter for residual current monitoring.
- 0–10 s adjustable operating delay.
- Designed for use with external ABB TR-series toroidal transformers.
- Compatible with ABB S200 MCBs and Tmax moulded-case circuit breakers up to T5.
- DIN-rail mounting with a three-module width.
- Complies with IEC/EN 60947-2 Annex M.
Flexible Residual Current Protection for Industrial Systems
The ABB RD3M-48 operates with an external toroidal transformer through which the active conductors of the protected circuit are routed. Under normal conditions, the currents through the toroid balance each other. An earth fault or insulation leakage creates a residual current imbalance that is detected by the transformer and transmitted to the RD3M-48 for evaluation.
Adjustable sensitivity and operating delay allow the relay to be configured for the requirements of the installation, while the 60% pre-alarm threshold provides advance warning before the main residual current operating level is reached. When used with an appropriate tripping device, the RD3M-48 can be combined with ABB S200 miniature circuit breakers and Tmax moulded-case circuit breakers up to T5 to provide coordinated residual current protection in industrial installations.
Typical Applications
- Industrial low-voltage distribution systems.
- Electrical switchboards and distribution panels.
- Industrial machinery and automation systems.
- Installations requiring residual current pre-alarm monitoring.
- Earth leakage monitoring with ABB TR-series toroidal transformers.
- Protection systems incorporating ABB S200 MCBs or compatible Tmax moulded-case circuit breakers.
