Basler Electric APR63‑5 – Automatic Voltage Regulator (9168700107)

The Basler Electric APR63‑5 is a solid‑state automatic voltage regulator (AVR) designed for precise control of synchronous generator excitation. Known by part number 9168700107, this regulator provides reliable voltage regulation for brushless and stationary‑armature generators in industrial, marine, and standby power applications. The APR63‑5 is renowned for its simplicity, ruggedness, and proven performance in demanding environments.

Voltage Regulation and Accuracy

The APR63‑5 maintains generator terminal voltage within ±1.0% of setpoint from no‑load to full‑load, with a response time of typically 0.3 seconds for a 10% load change. The regulation setpoint is adjustable via a front‑panel potentiometer, covering a range of 90‑260 V AC (single‑phase sensing) or 190‑520 V AC (three‑phase sensing). A built‑in stability control allows fine‑tuning of the dynamic response to match different generator and exciter characteristics.

Excitation Output and Power

The regulator provides a controlled DC output for the exciter field, with a continuous rating of 63 V DC at 5 A (peak current of 10 A for 10 seconds). This output is sufficient for generators up to approximately 300 kVA, depending on the exciter design. The output stage is fully protected against short‑circuit and overload, and includes a soft‑start function for controlled voltage build‑up.

Frequency Compensation and Underfrequency Protection

The APR63‑5 includes an automatic underfrequency compensation (UFRO) feature that reduces the voltage setpoint in proportion to frequency drop, preventing the generator from becoming over‑excited at low speeds. This protects the generator and connected loads during startup and overspeed conditions. The UFRO characteristic is adjustable via a trim potentiometer.

Input Sensing and Protection

Voltage sensing is provided via a single‑phase or three‑phase PT connection, with a nominal input range of 100‑480 V AC. The regulator is protected against reverse polarity, transient overvoltage, and short circuits on both the sensing and power supply inputs. A loss‑of‑sensing shutdown feature de‑energizes the exciter if the sensing voltage is lost, preventing runaway voltage conditions.

Adjustable Parameters and User Controls

Front‑panel controls include the voltage setpoint potentiometer, stability adjustment, and droop compensation trimmer (for parallel operation). LED indicators provide power, regulation, and fault status. The unit includes test points for monitoring the output voltage and current, simplifying field calibration and troubleshooting.

Parallel Operation and Droop Control

The APR63‑5 includes a reactive droop compensation function for parallel operation of multiple generators. The droop setting (0‑5%) is adjustable, allowing precise reactive load sharing without the need for external control circuits. This feature is essential for islanded generator installations where two or more units operate in parallel.

Mechanical and Environmental Design

Housed in a rugged steel case, the APR63‑5 is designed for panel mounting in switchgear and control cabinets. It operates in ambient temperatures from -20 °C to +65 °C and is rated IP20. The unit uses natural convection cooling, eliminating the need for fans and enhancing reliability in dusty or corrosive environments.

Typical Applications

This AVR is commonly used in diesel generator sets, hydroelectric turbines, and industrial standby systems. Its robust design and simple interface make it a favorite for retrofit applications and OEM installations where reliability is paramount.

Installation and Wiring

Clear terminal markings and a comprehensive wiring diagram simplify installation. The regulator requires connections to the generator PTs, the exciter field winding, and an auxiliary supply. All wiring is via screw‑type terminals with ample clearance for secure connections.

Compliance and Certification

The APR63‑5 complies with IEC 60034, UL 508, and CSA C22.2 standards, and carries CE and cULus certifications. It is designed to meet the requirements of marine classification societies such as DNV and ABS.

Maintenance and Service

With solid‑state construction and no moving parts, the APR63‑5 requires minimal maintenance. Periodic inspection of terminal connections and cleaning of the housing are recommended. Replacement parts, including potentiometers and fuses, are available from Basler Electric distributors.

Overall, the Basler Electric APR63‑5 offers a dependable, straightforward voltage regulation solution that provides stable generator operation in a wide range of applications.