High Temperature High Pressure Motor Design

Introduction

Offering comparable reliability but significantly higher efficiency and power density, permanent magnet brushless DC (BLDC) synchronous motors are increasingly replacing conventional asynchronous (induction) machines in general industrial applications. Studies show that BLDC motor efficiency ranges from 91 – 93% for highspeed applications and 85 – 89% for high torque applications, consuming an average of 23% less energy than an induction motor of equivalent power. Furthermore, BLDC motors have the capability of delivering full torque over the entire operating range including startup.

With the development of advanced construction materials such as high temperature magnets, magnet wire and insulation systems, designers are now applying BLDC motors in increasingly hostile environments. For example, typical application requirements for downhole tooling in the oil and gas industry can be summarized as follows:

  • Ambient Temperature: 150 to 220°C
  • Ambient Pressure: 10k-32k PSI
  • Open or Pressurized Construction
    • Open: submerged in oil, holes in housing to equalize pressure
    • Pressurized: sealed housing to keep motor interior dry
  • Voltage: 24 – 600 VDC
    • Lithium ion battery power source
  • Vibration: 25 G
  • Shock:
    • 100 G axial
    • 50 G radial
  • Diameter Constraint: 2” – 4”
  • External Housing Material: stainless steel
  • Feedback: Hall sensor, resolver or sensor-less
  • Magnet Material: SmCo
  • Life: 2,000 hours of operation between service intervals
To find out more about BLDC Motor Design Considerations for High Temperature/High Pressure Environments, please fill out the form below to receive our Whitepaper and learn more about:

  • Design Factors
  • Typical Design Construction
  • Housing/End Cap
  • Bearings
  • Stator Laminations
  • Stator Core and Assembly
  • Shaft
  • Magnets
  • Rotor/Stator Sleeves
  • Feedback Devices
  • Common BLDC Motor Failure Modes
  • Get the White Paper by filling out this form