Basler Electric SSR125-12 – High‑Power Static Voltage Regulator

The Basler Electric SSR125-12 (part number 918500102) is a high‑capacity static voltage regulator designed for large synchronous generators requiring field currents up to 125 A. This regulator is built around a heavy‑duty thyristor bridge with advanced gate‑drive circuitry, delivering stable, controlled excitation even under the most demanding grid and load conditions.

Power and Control Architecture

The SSR125-12 employs a digital control core that provides precise voltage regulation with fast transient response. Its sensing inputs accept standard PT and CT signals, and the regulator includes both automatic voltage regulation (AVR) and manual control modes. The unit features a comprehensive protection suite, including overvoltage, undervoltage, over‑excitation, loss‑of‑sensing, and SCR temperature monitoring. Communication interfaces enable integration with plant SCADA systems.

• Input voltage: 400/480/600 V AC, 50/60 Hz

• Output current: 125 A continuous (150 A surge)

• Output voltage: up to 300 V DC

• Regulation accuracy: ±0.25% of setpoint

• Response time: < 30 ms for 10% step change

• Protections: over/under voltage, over/under frequency, field overcurrent, SCR misfire, overtemperature

• Communication: RS‑485 Modbus and optional Ethernet

• User interface: digital display with keypad

• Cooling: forced air with temperature‑controlled fans

• Operating temperature: –20 °C to +60 °C

Application Areas

This regulator is ideal for utility‑scale generators, industrial cogeneration plants, and large marine installations. Its ability to handle high field currents makes it suitable for both brushless and static excitation systems. The SSR125-12 also supports reactive power control and voltage‑droop paralleling, essential for grid‑connected operation.

Installation and Configuration

Mounting requires a robust cabinet with adequate ventilation. All power connections are made via bus bars, while control wiring uses pluggable terminals. Configuration is performed through the front‑panel interface or via Basler's BESTCOMS™ software, allowing for comprehensive parameter customisation and event logging.

Reliability and Testing

Each SSR125-12 undergoes stringent factory testing, including high‑voltage dielectric, thermal cycling, and full‑load operation. Built to withstand harsh industrial environments, it complies with IEEE C37.90 and IEC 60255 standards. Basler's support ensures reliable operation throughout the unit's service life.

In summary, the Basler Electric SSR125‑12 static voltage regulator offers high‑power excitation control with advanced protection and diagnostics, making it a premier choice for large generator applications.