Basler Electric SR4A-2B03B3A – Compact Static Voltage Regulator

The Basler Electric SR4A-2B03B3A (also designated SR4A2B03B3A) is a compact, cost‑effective static voltage regulator designed for small to medium‑sized synchronous generators. It provides reliable excitation control with a straightforward adjustment interface, making it an excellent choice for standby sets, agricultural generators, and light industrial applications.

Design and Performance

The regulator utilises a pulse‑width modulated (PWM) power stage for high efficiency and low heat dissipation. Its sensing circuit accepts standard 120/240 V AC inputs and delivers a regulated DC output to the generator field. The SR4A‑2B03B3A includes adjustable voltage setpoint, stability (gain) control, and under‑frequency roll‑off to protect the generator during overspeed conditions. A built‑in soft‑start feature gradually applies excitation to reduce mechanical stress on the prime mover during startup.

• Input voltage: 120/240 V AC, 50/60 Hz

• Output current: 3 A continuous (5 A for 10 seconds)

• Output voltage: up to 90 V DC

• Regulation accuracy: ±1% from no‑load to full‑load

• Voltage adjustment: ±10% of nominal

• Stability adjustment: continuous trimpot

• Under‑frequency roll‑off: 45–60 Hz adjustable

• Protections: over‑excitation limiting, short circuit

• LED indicators: power and regulation status

• Mounting: panel mount with heat sink

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

Application Scope

This regulator is ideal for generators up to 300 kVA in applications such as construction sites, farms, telecom towers, and small commercial buildings. Its simple configuration makes it suitable for field replacement of older electromechanical regulators, offering improved performance and reliability with minimal wiring changes.

Installation and Tuning

Mounting is straightforward with four screws, and all electrical connections are made via pluggable terminal blocks. Three trimpots—for voltage, stability, and frequency roll‑off—allow quick field tuning. Diagnostic LEDs assist in verifying correct operation during commissioning.

Durability and Compliance

The SR4A-2B03B3A is built with high‑quality components and features conformal coating to resist moisture and dust. It complies with CE and RoHS directives, ensuring environmental safety. Basler’s rigorous testing guarantees reliable performance in demanding conditions.

In conclusion, the Basler Electric SR4A-2B03B3A static voltage regulator offers a compact, reliable solution for generator excitation control, combining ease of use with proven Basler quality.