The Step-Pak SPD-6U Stepping Motor Driver is a high efficiency, high performance motor driver. The engineered uni-polar, bi-level design provides absolutely minimum motor and driver losses which result in cool running motors and drivers, enabling high density packaging of equipment. Low DC voltage is applied to the motor windings when the motor is positioned. High voltage is applied synchronously with motor steps for fast acceleration and high running torque. Most of the switching losses inherent in chopper type drives is eliminated resulting in cooler running motors. The bi-level motor drive produces very low levels of radiated electrical noise which is critical during scientific data collection. When the motor is held at position, no currents are interrupted, therefore there are no radiated electromagnetic fields to interfere with measurements.