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28 Amp DIGITAL High Frequency PWM Motor Speed Controller w/ Soft Start

Quantity Discount     Unit Price
List Price:   $74.95
1   $67.95
Without Soft-Start
P/N: SPD-328-D

With Soft-Start
P/N: SPD-328-DS

Datasheet (PDF)

Control the speed of a DC motor using a potentiometer, 0-5V signal, push buttons or logic pulses from a microcontroller. This controller features a silent PWM switching frequency for use in noise-sensitive applications. It can also be used as a low voltage light dimmer for halogen lamps, or for controlling heaters and irons.

This controller operates in the same way as the basic digital model (SPD-2115B-ED) but due to the high frequency switching, there is no audible PWM noise. The higher frequency also allows for smoother current in the motor and a higher system efficiency.

Automatic Soft-Start is available on P/N SPD-328-DS. The Soft-Start option slowly ramps up power to reduce stress on power supplies and mechanical linkages.

4 Ways to Control:

  • Analog:
    • Potentiometer
    • 0V - 5V analog voltage level
  • Digital Mode:
    • Push Buttons - UP and DOWN buttons buttons to control speed
    • Logic Mode - pulse the UP or DOWN lines to change speed

Additional Features:

  • Silent PWM switching frequency for quiet operation
  • Analog or Digital Modes selectable via jumpers
  • Digital input filtering allows smooth control even with noisy inputs
  • Logic Controller Enable input
  • Low Impedance, Long Life filter capacitor for maximum reliability
  • High efficiency MOSFET design and Heavy-Duty Heatsinks for cool operation


  • 28 Amps continuous current
  • 5.5 - 30 VDC operation
  • 18 kHz switching frequency
  • PWM Range: 0% - 100%
  • Single direction (no reverse)


  • Terminal blocks for signal and power connections

Technical Documents:

Datasheet (PDF) (requires Adobe Acrobat Reader)

Application Notes:

When choosing a controller based on your input voltage requirements, please note that a fully charged 12V nominal lead-acid battery can reach 14 volts. Please check to ensure that the battery pack voltage does not ever exceed the absolute maximum rated voltage of the motor controller.


2.3 x 3.1 x 2.2 inches tall.

For a comparison of motor control features, check out the parametric selection guide.

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