Description
ABB REX010 HESG324426M1
REX010 Module (Part Code: HESG324426M1) Introduction
1. Product Overview
REX010 with part marking HESG324426M1 is a pluggable auxiliary I/O expansion module designed to work with numerical protection relays in medium voltage secondary control systems. It is installed on the base unit of compatible protection devices via internal card slots, used to extend digital input and relay output capacity for realizing complex interlock, alarm and status signal transmission functions. The module adopts compact board-on-base design and is exclusively intended for installation inside indoor switchgear cabinets.
ABB REX010 HESG324426M1
2. Hardware Layout & Interface Features
The module is fitted with dedicated terminal blocks for field wiring, divided into power supply terminals, digital input terminals and relay output terminals. Internal isolation circuits separate field secondary wiring signals from the main processing unit of the protection relay to suppress high electromagnetic interference generated by breakers and contactors. Multiple built-in miniature electromagnetic relays provide isolated passive contact outputs. Visible LED status indicators on the front panel display module power status and individual channel activity, enabling on-site quick fault inspection without extra testing instruments. Internal surge suppression and short-circuit protection circuits prevent hardware damage caused by reversed wiring or short-circuit faults in secondary loops.
3. Key Electrical Specifications
- Power supply: Wide-range AC/DC universal supply matching standard substation control power sources
- Digital input channels: Multiple passive voltage sensing inputs for collecting breaker position, disconnector status and external fault contact signals
- Output contacts: Galvanically isolated relay contacts suitable for switching low-power AC and DC control circuits
- Operating temperature range: -20°C to +70°C for continuous cabinet operation
- Enclosure protection class: IP20, restricted to indoor cabinet mounting only
- Galvanic isolation between field wiring and internal logic circuits to withstand industrial switching surges
4. Core Functional Capabilities
- I/O capacity expansion: Adds extra digital input and relay output channels to the main protection relay, resolving insufficient native I/O points for complicated interlock logic.
- Electrical signal isolation: Blocks voltage surges and noise from field hardwiring to protect the core control board of the main relay unit.
- Auxiliary signal conversion: Converts internal logic signals from the protection relay into dry contact signals to drive on-site alarm indicators, interlock circuits and remote signalling loops.
- Real-time channel supervision: Continuously monitors module power supply and each signal channel, uploading abnormal channel status to the main relay for fault logging and local alarm indication.
- Secondary circuit compatibility: Matches standard secondary circuits of current transformers, voltage transformers and all common switch auxiliary contact signal types used in power distribution systems.
5. Typical Application Scenarios
This module is deployed in medium voltage distribution switchgear, industrial power distribution rooms and compact box substations. It pairs with feeder, transformer and medium-voltage motor protection relays to handle multi-point equipment status collection and multi-group remote alarm output. Common use cases include ring main unit interlock control, transformer temperature alarm signal expansion and continuous monitoring of breaker trip circuit integrity.
6. Basic On-Site Fault Troubleshooting
- Power LED off: Loss of module supply, poor slot contact or internal power circuit failure
- No channel LED response: Broken external wiring, faulty field auxiliary contacts or damaged channel circuitry
- Failed relay output: Burned contact points, overloaded output loop current or wiring short-circuit
- Unstable flickering signals: Missing cable shielding, inadequate circuit isolation or heavy on-site electromagnetic interference
