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KBWT-112 KB Electronics Pulse Width Modulated (PWM) Whisper-Drive, 8612

Product ID: KB8612

MFG: KB Electronics, Inc
MFG Part Number: 8612

Available Stock: 1
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$185.22 / Each
115VAC 50/60Hz 18 Amp Input, 12 Amps @ 90VDC Ouptut, 1.5HP Continuous Duty


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.


Manufacturer KB Electronics
Part Number 8612
Model Number KBWT-112
AC Line Input 115 VAC (+10% / -15%)
Maximum AC Line Current 18.0 RMS Amps
Maximum DC Output Current 12.0 Amps @ 90VDC
10.5 Amps @ 130VDC
Max Current Limit Setting 25.0 Amps
Maximum Motor Size 1.5 HP (1.1kW) Continuous Duty
2.5HP (1.9kw) Intermittent Duty (1 Minute)
Armature Fuse Rating 25 Amps
Warranty Limited Warranty


Speed Range 50:1
Operating Frequency less than 16kHz
Form Factor less than 1.05 RMS/Avg Amps
Operating Temperature 0 to 45°C
Load Regulation 1% of Base Speed
Acceleration Range Fixed
0, 0.2, 2.5, 7 or 10 Seconds
MIN Speed Trimpot Range 0 to 30% of Full Speed
MAX Speed Trimpot Range 50 to 100% of Full Speed
CL Range 0 to 200%
Motor Overload Protection Time Fixed
3, 5 or 10 Seconds
IR Compensation Range 0 to 15VDC
AC Line Voltage Regulation 0.5% Base Speed
Analog Input Voltage 0 to 5VDC
Voltage Following
Speed Potentiometer 1/4 Watt
5k Ohms

Standard Features

  • Short Circuit Protection
  • Electronic Motor Burnout Protection (I x t)
  • LED’s for “Power On” and Overload (OL)
  • Active Bridge: Provides controlled AC line inrush current limiting
  • Power Transistor Short Circuit Runaway Protection
  • eat-Spreader: Prevents power transistor failure due to overloads
  • Under Voltage Protection
  • Adjustment Trimpots:
    Minimum Speed (MIN)
    Maximum Speed (MAX)
    IR Compensation (IR)
    Current Limit (CL)