The 15 g-ton centrifuge, operational since 1981, is a Genisco 1230-5 accelerator modified for geotechnical applications. The symetrical dual-swing basket design will accelerate a 300 lb (136 kg) 18x17.5x23 in. (45.7x44.5x58.4 cm) payload to 100g. A 25 horse-power (18.6 kW) electric motor with a toothed-belt drive was recently incorporated to power the 15 g-ton centrifuge. This system provides programable g vs. time profiles like 400g-ton and instructional centrifuges. Closed loop control also provides accurate speed regulation immume to line voltage variations that cause speed instabilities in the current system.