The KBWM™ Vari-Drive™ adjustable speed SCR control for DC motors offers proven reliability in a rugged all-metal NEMA-1 enclosure.  The Vari-Drives are equipped with the ultimate KBMM™ speed control module.  They are specifically designed for fractional horsepower permanent magnet (PM) DC motors. Two models are offered. The KBWM-120 is designed for 115 VAC input and is rated 1/100 – 1/3Hp at 90 VDC. For motors rated 1/50 – 3/4 Hp at 180 VDC use Model KBWM-240.

KBWM Operation


KB’s exclusive Plug-in Horsepower Resistor® automatically presets the drive’s IR Comp and CL circuits for safe operation on various motors.  Although factory calibrated, internal trimpots for Min, Max, IR, CL, Accel and Decel can be used to fine-tune the KBWM™ for specific applications.  Connections to the control are via a barrier terminal block. By changing the orientation of the front cover, the wiring can be brought in either from the bottom or the top of the control.

Motor failure due to demagnetization is eliminated by the patented ultra-fast Direct-Fed™ current limit circuit. The controls contain AC line and armature* fusing, which provide protection against catastrophic failure. Auto-Inhibit®, a KB exclusive, allows the drive to be turned on and off rapidly using the AC line without damage to the control and/or motor. The internal CL LED is a diagnostic indicator that lights when the motor is overloaded. A conveniently located front panel lighted rocker switch controls AC line input power to the drive.

KBWM Links

KBWM datasheet kbwm

KBWM manual kbwm manual