Steady Bushing Technical Information for Vertical HOLLOSHAFT® Motors

This technical document from Nidec Motor Corporation outlines the design, function, and installation guidance of steady bushings used in vertical HOLLOSHAFT® motors. It explains when and why steady bushings are critical, particularly in high thrust pump applications, and highlights the compatibility with various motor frames and coupling types.

Key Points

  • Steady bushings are essential for applications with mechanical seals in the pump discharge head.
  • Compatible with bolted couplings and non-reverse ratchet (NRR) motors, but not with self-release couplings (SRC).
  • Not field-installable on some motors with oil bath lower bearings (e.g., 5000 TEFC, 5800, 6800 ODP).
  • Serve dual roles as stabilizer and water slinger, ensuring mechanical integrity.
  • They reduce shaft whip and minimize shaft resonance in long-span installations.
  • Constructed from SAE 660 bearing bronze and available for grease-lubricated lower bearing motors.
  • Installed at the motor base and precision-aligned to within 0.002 inches TIR.
  • Should be included in quotes where mechanical seals are specified by OEMs.