Superior Electric Powerstat Motorized Variable Autotransformer 21-1021-MD

The Superior Electric Powerstat 21-1021-MD is a motorized variable autotransformer designed for precise control of AC voltage in industrial and laboratory applications. This single-phase unit operates on 120V input, providing adjustable output from 0-120V at up to 5.5A and 0.66 kVA. It features a motor operator for automated adjustment, with a travel time of 12 seconds for full range traversal, making it ideal for applications requiring remote or programmed voltage variation, such as testing equipment, lighting controls, and process automation. Key benefits include smooth voltage regulation without waveform distortion, high efficiency, and robust construction for reliable performance in demanding environments. Compared to similar products like Variac transformers, the Powerstat offers superior build quality and motorization for hands-free operation, though it may require periodic maintenance due to its mechanical components. Drawbacks include its vintage design, which might limit compatibility with modern digital controls without adaptations. This unit is suitable for benchtop use in electronics testing, motor speed control, and power supply simulation, providing accurate and repeatable voltage adjustments.