Maintain a micro-hydro plant on a fixed schedule: check the trash rack daily, the bearings and penstock weekly, the settling basin and electrical connections monthly, and the turbine runner and penstock supports yearly. With that routine the carrier puts the life of a well-built system at 20 to 50 years.
Part of Micro-Hydro Turbine
Hydro maintenance is a short list of regular inspections along the path the water takes, from the intake to the tailrace and the generator.
The Schedule Follows The Water
The carrier describes micro-hydro systems as remarkably low-maintenance, and says a well-built system with basic maintenance can operate for 20 to 50 years. Its schedule, with where each job is covered:
| Interval | Job | Detail |
|---|---|---|
| Daily | Clear the trash rack, especially after rain | Debris & Ice Management |
| Weekly | Check bearings for wear and oil them if needed | Bearing Maintenance |
| Weekly | Inspect the penstock for leaks | Penstock Leak Repair |
| Monthly | Clean the settling basin | Intake & Trash Rack |
| Monthly | Inspect electrical connections | Electrical Safety |
| Yearly | Inspect the runner for erosion, especially in sandy water | Turbine Types |
| Yearly | Check the penstock supports | Penstock Design & Materials |
Sand in the water erodes the runner, which is why the carrier singles out sandy water, so a basin cleaned on time protects the most expensive part.
Three Log Entries Warn Of Trouble Early
Write down every inspection: date, what was found, what was done. Three things in the log pay for themselves:
- The shaft speed and output at a fixed flow. A slow decline in power at the same gate setting is the earliest warning of wear or a leak.
- The pressure gauge reading at the powerhouse with the turbine gate closed. It should equal 1 bar per 10.2 m of head (Head Measurement (Elevation Drop)). A fall means a leak.
- The coast-down time after the gate closes. A shorter time means a bearing is dragging.
A Symptom Points To The First Thing To Check
| Symptom | First thing to check |
|---|---|
| Output falling over days | rack and basin blocked; penstock leaking |
| Output falling over years | runner worn by sand; nozzle worn |
| Humming or shaking | bearing, misalignment or loose belt |
| Voltage swinging | dump load or controller; see Load Control |
| Plant silent in cold weather | ice on the rack or intake |
Common Mistakes
- Waiting for a failure to look — the schedule catches wear before it stops the plant.
- Working on a running machine — shut the water first.
- No spares — a belt, a set of bearings and a gasket kept on the shelf turn a week-long stop into an hour.
Safety
Stop the water before touching anything
Close the intake gate and the turbine gate, wait for the runner to coast down, then work. Treat the generator output as live until the water has stopped and the load is disconnected. Never put a hand into a rack, nozzle or belt while the water is running.
What’s Next
- Learn next: Bearing Maintenance for the weekly bearing job
- Combine with: Civil Works for the structures the schedule walks along