Electric drive technology options for plastics machines

Challenge:

Understand the range of technologies now available to drive hydraulic systems on plastic production machines and which solution is best for an application

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Rexroth Solution

  • Variable Frequency Drives (VFD) utilizing V/f technology
  • VFD Drives using Vector Drive Technology
  • Electric Servo Drives

Key Insights & Considerations:

  • A range of technologies is now available to drive hydraulic systems on plastic production machines, offering higher speeds, greatly improved energy efficiencies and higher reliability
  • Variable frequency drives (VFDs) vary the frequency of the drive output to vary the motor RPM; they are relatively low-cost but only provide speed accuracies of around ten percent
  • Vector drives use microcontrollers to precisely manipulate drive output to control torque of a standard AC induction motor
  • Servo drives offer a high speed range, maximum torque available at zero RPM, and very high dynamics
  • Servo drives are more costly and require more complex drive electronics; they offer the ability to precisely control speed, torque and position of the servo motor.
  • In certain molding machines, servo drives used with variable displacement pumps dynamically control pump speed to match the varying flow and pressure requirements through the course of a machine’s duty cycle, reducing energy consumption and operating more efficiently