Basler Electric SSR 125-12 Voltage Regulator

The Basler Electric SSR 125-12 is a solid-state automatic voltage regulator designed for small to medium synchronous generators with ratings up to approximately 125 kVA. It maintains the generator output voltage within ±1% of the setpoint from no-load to full-load, ensuring stable power supply for sensitive loads. The regulator is simple to install and adjust, making it a popular choice for standby, portable, and marine generator sets.

Regulation and Control

The SSR 125-12 uses a proportional-integral control circuit with adjustable stability to accommodate different exciter and generator characteristics. A front-panel potentiometer allows voltage setpoint adjustment from 90% to 110% of nominal. An under-frequency roll-off function reduces excitation when the frequency drops below 45 Hz, preventing motor over-excitation and protecting the generator during speed dips.

Input and Output

Sensing input: 120-240 VAC, single-phase, 50/60 Hz. The regulator derives its power directly from the sensing input, eliminating the need for a separate power supply. Excitation output: up to 90 VDC at 12 A continuous, sufficient for most brushless exciters. Output is short-circuit protected and current-limited. A field current monitor terminal allows connection to an external meter.

Protection Features

Built-in protections include short-circuit protection on the field output, over-voltage clamping, and thermal overload. A red LED indicates a fault condition, and a green LED confirms normal operation. The regulator automatically resets after fault clearing. An auxiliary output can be used to drive an external alarm.

Technical Specifications

Operating temperature: –40°C to +65°C. Regulation accuracy: ±1%. Response time:<80 ms for 20% load change. Burden: <5 VA. Enclosure: rugged plastic or metal, suitable for panel or chassis mounting. Dimensions: 120 mm x 80 mm x 40 mm (typical). Compliance with CE and RoHS standards.

Applications

Ideal for diesel generators, gasoline generators, and marine auxiliary sets, this regulator is also used in agricultural pumping, construction power, and telecommunication sites. Its compact size allows installation inside the generator terminal box. It is also used in wind turbine and hydroelectric small-scale installations.

Installation and Adjustment

Mount the regulator on a flat surface using the four mounting holes. Connect the AC sensing wires to the generator output and the field wires to the exciter. Adjust the voltage setpoint with a screwdriver while monitoring the generator output voltage. The stability control is set to achieve a stable response without hunting. A test mode is available for verification.

Reliability and Durability

Basler Electric’s SSR 125-12 is built with high-quality components and conformal-coated PCBs to withstand moisture and dust. It operates reliably in ambient temperatures from –40°C to +65°C. With no moving parts, it offers long service life and minimal maintenance. Each unit is factory tested for performance and insulation.

Conclusion

The Basler Electric SSR 125-12 voltage regulator is a dependable, cost-effective solution for voltage control in small generator applications. Its straightforward design, robust protection, and easy adjustment make it a preferred choice for original equipment manufacturers and end users alike.