THIS DRIVE WILL NOT OPERATE WITHOUT A PLUG-IN HORSEPOWER RESISTOR and an ARMATURE FUSE. Horsepower resistors and armature fuses are available for purchase from our Amazon store. KBWD-13 DC Drive PWM (Pulse Width Modulated) The KBWD-13, 16 models provide a low cost alternative for pulse-width-modulated (PWM) control applications. Their compact size allows for direct replacement of other types. Standard features include instantaneous short circuit protection, under voltage protection and KB's Plug-in Horsepower Resistor®, which eliminates the need to calibrate IR Comp and CL. A potentiometer (5k), isolated analog signal (0-5VDC) or PWM microprocessor output can be used as an input signal. Dimensions: 4.30" x 3.60" x 2.50"