Half Shaft Sleeve Retrofit for Bidirectional Pump-Turbine

Techemer successfully delivered a half shaft sleeve retrofit solution for a large vertical adjustable mixed-flow pump-turbine unit operating within a major national water transfer system.

The unit is powered by a 3550 kW / 10 kV synchronous motor and operates under bidirectional conditions, alternating between pumping and power generation.

This project represents the first retrofit application of a half sleeve structure for a comparable high-capacity pump station.

Operational Challenge

The unit operates at:

• 125 r/min rotational speed
• 30 m³/s generating flow
• Dual-function mode (pumping + power generation)

Conventional solid shaft sleeves require complete dismantling of the motor and coupling assembly during maintenance, leading to extended shutdown periods and high service costs.

For large infrastructure assets, downtime directly translates into operational and economic impact.

Techemer Engineering Solution

Techemer introduced a symmetrically half shaft sleeve designed for on-site installation without removing the motor or coupling.

Key Engineering Benefits

• Installation time reduced to 20% of traditional methods
• Significant reduction in unit downtime
• High-strength bolted fastening system
• Advanced wear-resistant coating technology
• Withstands bidirectional load impact and cyclic stress
• Precision concentricity adjustment to minimize vibration
• Field performance exceeding industry wear standards

Engineering Impact

This retrofit solution:

• Enhances reliability in dual-mode pump-turbine systems
• Extends shaft-line service life
• Minimizes lifecycle maintenance costs
• Provides a scalable modernization path for existing pump stations

Techemer's shaft sleeve technology demonstrates how targeted mechanical innovation can significantly improve uptime and long-term infrastructure stability.