THIS DRIVE WILL NOT OPERATE WITHOUT A PLUG-IN HORSEPOWER RESISTOR. Horsepower resistors are available for purchase from our Amazon store. The KBMM-125 Adjustable Speed DC Drive will control motors between 1/100-3/4 HP (1.5 HP w/aux. Heat-sink) by inserting the proper Plug-in Horsepower Resistor. The KBMM-125 motor speed control is designed for 90 VDC PM & Shunt motors. Speed range is 50:1 with load regulation of 1%. Features include: AC Line fuse and Armature Fuse holder, Auto Inhibit, Voltage Following, MOV transient protection, 5K speed pot and trimpot adjustments for Min, Max, Accel, Decel, IR and CL. Options include Auxiliary heat sink, Barrier Terminal Board, RFI/EMI filters and Signal Isolation (model SI-6). This control is available worldwide from stocking KB distributors. UL, CSA, CE, C-tick. Patented.