June 08, 2026

ABB UNITROL 1020 3BHE030579R0006 Digital Excitation Controller

The ABB 3BHE030579R0006 (UNITROL 1020-0006 FULL, UNS0119) is a compact, high-performance digital automatic voltage regulator (AVR) and excitation controller designed by ABB for synchronous generators in static excitation systems. It delivers precision voltage regulation, reactive power control, and system stability for small-to-medium power plants, industrial generators, marine propulsion, and traction applications. As a key member of the UNITROL 1000 series, it builds on decades of ABB power electronics expertise, offering a fully digital control architecture, fast dynamic response, and comprehensive protection in a rugged, space-saving form factor.

Description

ABB UNITROL 1020 3BHE030579R0006 Digital Excitation Controller

Overview

Key Features

High Precision Regulation: Achieves voltage regulation accuracy of ±0.5% of setpoint (±0.2% at 25°C) with a fast response time of <50 ms, ensuring stable generator terminal voltage under varying load and grid conditions.
Multiple Control Modes: Supports automatic voltage regulation (AVR), manual excitation current control, reactive power (VAR) regulation, and power factor control with bumpless mode switching for flexible operation.
Advanced Protection: Integrates 20+ protection functions including over-excitation limitation, under-excitation protection, overvoltage/undervoltage, overcurrent, field short-circuit, and loss-of-excitation protection, safeguarding generators and excitation equipment.
Rich I/O Interfaces: Equipped with 12 digital inputs, up to 8 configurable digital outputs, 3 analog inputs, and 2 analog outputs for seamless connection to sensors, switches, and control devices.
Industrial Communication: Features Modbus RTU (RS-485), USB, and optional Ethernet interfaces for data exchange with PLCs, SCADA, and DCS systems; configured via ABB CMT1000 software for real-time monitoring and parameter tuning.
Rugged Construction: Conformal-coated PCB, IP20 protection, and a wide operating temperature range of -25°C to +70°C (extended -40°C to +70°C available) ensure reliability in harsh industrial environments.
Compact & Standardized: Panel/rack mount design with dimensions 210 × 160 × 90 mm and weight ~3.5 kg, enabling easy installation and direct replacement of legacy UNITROL series units.

Technical Specifications

Manufacturer: ABB
Model: 3BHE030579R0006 (UNITROL 1020-0006 FULL)
Product Type: Digital Excitation Controller / Automatic Voltage Regulator (AVR)
Rated Control Power: 12.5–48 VDC; 120/240 VAC optional
Maximum Continuous Field Current: Up to 500 A (system-dependent)
Voltage Regulation Accuracy: ±0.5% (±0.2% at 25°C)
Response Time: <50 ms for three-phase measurements
Control Modes: AVR, Manual, VAR, Power Factor
Digital I/O: 12 inputs, up to 8 outputs
Analog I/O: 3 inputs, 2 outputs
Communication: Modbus RTU (RS-485), USB, Ethernet (optional)
Protection Class: IP20
Operating Temperature: -25°C to +70°C
Dimensions: 210 × 160 × 90 mm
Weight: ~3.5 kg
Certifications: CE, UL, RoHS, DNV

Core Functions

The primary function of the 3BHE030579R0006 is closed-loop excitation control for synchronous generators. In automatic mode, it samples generator voltage, current, and grid signals in real time, executes adaptive control algorithms, and adjusts thyristor conduction angles to stabilize output voltage within rated limits. Manual mode allows technicians to set excitation current directly for commissioning, testing, or emergency operation.

Beyond regulation, it provides comprehensive system monitoring and fault management. It continuously tracks excitation system health, triggers protective actions and alarms during abnormalities, and logs fault data for diagnostics. It also supports synchronization and load sharing control, ensuring coordinated operation with other power system components.

Typical Applications

Power Generation: Thermal, hydro, and combined-cycle power plants; industrial captive power stations.
Marine: Electric propulsion systems and auxiliary power supplies for vessels.
Traction: Diesel-electric locomotives and rail power systems.
Distributed Power: Diesel/gas generator sets, wind turbine synchronous generators.
Retrofit & Upgrade: Direct replacement for legacy ABB UNITROL 1000-7/15 series AVRs, with full backward compatibility for electrical interfaces and software.

Compatibility

The 3BHE030579R0006 is fully compatible with ABB UNITROL series excitation system components, including rectifier modules, power supply units, and backplane assemblies. Its signal definitions, I/O specifications, and communication protocols align with the UNITROL 1020 platform, enabling plug-and-play replacement. It also integrates seamlessly with third-party PLCs, SCADA, and HMI systems via standard industrial protocols.

Advantages

Proven Reliability: Field-proven design with high-quality components and strict manufacturing standards ensures long-term, maintenance-free operation.
Enhanced Grid Stability: Fast response and precise regulation minimize voltage fluctuations, improving power quality and grid compatibility.
Simplified Maintenance: Compact design, user-friendly CMT1000 software, and built-in diagnostics reduce commissioning and troubleshooting time.
Cost-Effective Upgrade: Direct replacement for older UNITROL models eliminates the need for extensive wiring or control logic modifications, lowering downtime and costs.
Global Support: Backed by ABB’s worldwide service network, including 24/7 technical support and spare parts availability.

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