Project Description


Certain power tools can create a major safety hazard if not shut off properly before plugging them back into AC power. An angle grinder at full starting torque can become a heavy projectile if not secured properly by the operator. This customer wanted to offer a safer product as well as provide enhanced features such as variable speed, thermal overload protection, and the all-important restart prevention. DEIL’s two decades of motor control experience developed a compact, variable select switch control that prevents the motor from restarting when there is loss of power without switching the tool off.


  • Needed universal motor control experience
  • Compact design for power tool: HMI and closed loop PID motor control
  • Critical speed control at various settings
  • No restart when power is disrupted – safety critical
  • Requires ‘soft start’ to improve operator control
  • Built in over-heating cut off control
  • Dust and vibration proof design

Services Performed

  • ODM design
  • Hardware, software and mechanical design
  • Certification testing
  • Tooling


  • Custom designed compact step/thumbwheel speed control for rugged grinder application
  • Features included: restart prevention, soft start, thermal/over-heating shut off
  • Speed/torque precise control with closed loop PID circuit

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