This category includes analog potentiometers and digital electronic potentiometers used to adjust the speed reference of variable frequency drives. Analog models provide manual adjustment using a rotary knob, while electronic models allow reference adjustment through numerical settings or buttons. These products send a command to the drive's control input; they do not supply power directly to the motor.

For analog models, consider resistance, taper, power rating, shaft design and panel mounting dimensions together. A linear taper is generally preferred for speed adjustment. Select the resistance in kΩ according to the drive manual; one resistance range does not suit every drive.

For electronic models, check the supply voltage, 0–10 V or 4–20 mA output type, permitted output load and drive analog input settings. Display scaling, ramps, external button connections and retention of settings after power loss depend on the model. If isolation is required, verify which circuits are isolated from each other in the product documentation. These devices must not be used as adjustable power supplies.

For wiring, connect the ends of the analog potentiometer's resistive track to the specified reference supply and analog common, and connect the wiper to the voltage input, following the drive manual. Wire electronic devices according to their model-specific supply and signal diagrams; voltage and current outputs are not interchangeable.

Models with scaling can display a value corresponding to machine speed. This remains a reference setting; it is not a measurement of actual speed without separate feedback.