KBWT High Current
Pulse Width Modulated Whisper-Drive

The KBWT Pulse Width Modulated (PWM) DC motor speed controls provide excellent dynamic response to load variation. The efficient PWM waveform produces an almost pure DC current to the motor (form factor < 1.05), which has several advantages over a conventional SCR control. PWM significantly lowers audible motor noise and provides longer brush life. It also produces less motor heating allowing a smaller, less costly motor to be used for most applications. Another advantage of PWM is higher output voltage, which provides increased output speed. In addition, pulse-by-pulse current sensing provides short circuit protection and prevents control damage due to shorted motors.

A unique feature of the KBWT Series is its active bridge, which provides a substantial reduction in AC line surge current each time the control is turned on. This allows the control to be turned on or off rapidly without damage to critical components.

The KBWT also contains a built-in safety circuit that will shut down the control if the main power transistor short circuits. This prevents high-speed runaway, a potential problem with competitors’ controls. The KBWT utilizes heat-spreader construction. This system provides an enhanced thermal path that eliminates overtemperature cycles which cause premature failure of the power transistors.

Other features of the KBWT are (I x t) motor burnout protection, which will shut the control down if the motor is overloaded for a predetermined time, and the Potentiometer Safety Circuit™ (optional), which prevents the control from starting when the AC line is applied unless the speed potentiometer is reset to zero. Diagnostic LED’s for “Power On” and “Overload (OL)” indication are also provided. The control contains quick disconnect terminals as standard. A potentiometer (5K), isolated analog input signal (0-5 VDC), or PWM microprocessor output can be used to vary the output of the control.

   Download the KBWT specification sheet in *.pdf format