Basler Electric MOC3502 – Motor‑Operated Potentiometer for Remote Setpoint Control

The Basler Electric MOC3502 (part number 90‑72300‑116) is a precision motor‑operated potentiometer designed to facilitate remote or automatic adjustment of control setpoints in a variety of industrial and power generation applications. By translating electrical raise/lower commands into precise mechanical rotation, this device enables operators to fine‑tune voltage regulators, speed governors, and process controllers from a distance, enhancing system flexibility and reducing the need for manual intervention.

Design and Operational Mechanics

The MOC3502 integrates a high‑quality, low‑torque potentiometer with a reversible DC motor and a durable gear train. The motor responds to momentary contact signals (open/close or raise/lower) from a remote switch, PLC, or supervisory control system, rotating the wiper arm to the desired angular position. An internal feedback potentiometer can be used for position indication or closed‑loop control, while built‑in limit switches prevent over‑travel and protect the mechanism from mechanical stress. The unit is designed for continuous duty and offers smooth, linear resistance characteristics.

• Resistance element: 5 kΩ (standard, linear taper)

• Motor supply: 120 V AC or 24 V DC (field‑selectable)

• Actuation time: 1–3 seconds for full 90° rotation

• Feedback option: 0–10 V DC or 4–20 mA (signal conditioner required)

• Mechanical travel: adjustable end stops (300° max)

• Torque: 5 N·cm (sufficient for most regulator inputs)

• Limit switches: two built‑in, rated 1 A at 30 V DC

• Electrical connections: screw terminals for motor, potentiometer, and limit switches

• Mounting: panel or bracket, with standard flange

• Operating temperature: –10 °C to +55 °C

Primary Application Scenarios

In generator excitation systems, the MOC3502 is frequently used to adjust the voltage setpoint of Basler SSR, SR, or DECS regulators, allowing operators to raise or lower the generator terminal voltage from a control room. It is also employed in speed control loops for diesel or hydro turbines, and in industrial process control for adjusting temperature, pressure, or flow setpoints. The device’s ability to accept remote signals makes it a key component for automated load‑sharing and sequencing schemes.

Integration and Wiring

Mounting is simple using the pre‑drilled flange holes, and the compact footprint allows installation within standard control cabinets. The terminal block is clearly marked for motor power (raise/lower), potentiometer taps (wiper, CW, CCW), and limit switch connections. The MOC3502 can be directly interfaced with Basler regulators using two‑wire or three‑wire control circuits. An optional manual knob provides local override capability, ensuring operator control during maintenance or emergency situations.

Durability and Performance Assurance

Manufactured with precision‑cut gears, sealed ball bearings, and a precious‑metal wiper, the MOC3502 offers exceptional mechanical life (over 1 million operations) and stable electrical characteristics over time. Each unit is tested for insulation resistance, dielectric strength, and torque linearity before shipment. Basler Electric’s rigorous quality control ensures that this motor‑operated potentiometer provides reliable, repeatable setpoint control in demanding electrical environments.

In conclusion, the Basler Electric MOC3502 motor‑operated potentiometer is a versatile and dependable solution for remote setpoint adjustment, combining precise mechanical positioning with robust construction to enhance the operational flexibility of generator and industrial control systems.