Dart Controls 253G-200E NEMA 4 DC motor speed control, 1/8 - 2HP, rotary speed pot The 250 Series offers superb flexibility, reliability, and value. A general purpose, economical control rated to 2 horsepower, it provides the ultimate in standard features and versatility including: dual voltage (120/240VAC), adjustable H.P. settings, packaged power bridge, barrier terminal strip, fully rated..