What machines does ISO 20816-5 cover?

ISO 20816-5 applies to hydraulic machines including vertical Kaplan turbines, vertical Francis turbines, vertical pump-turbines, horizontal Pelton turbines, and vertical pumps operating in hydroelectric power plants. It covers machines with rated speeds typically from 60 to 1000 RPM.

Why are hydro turbine vibration limits different from steam turbines?

Hydraulic machines operate at much lower speeds than steam turbines (often 60–500 RPM vs 1500–3600 RPM). They also experience hydraulic excitation forces from water flow, draft tube surges, and cavitation, which generate different vibration patterns. Vertical machines have additional considerations for thrust bearing vibration.

What is shaft displacement measurement in hydro turbines?

Shaft displacement in hydro turbines is measured using proximity probes mounted near the guide bearings, typically measuring peak-to-peak displacement in micrometers (μm p-p). This is critical for vertical machines where shaft orbit monitoring reveals unbalance, misalignment, and hydraulic instabilities.

Why do horizontal Pelton turbines have different limits?

Horizontal Pelton turbines have lower vibration limits than vertical machines because horizontal bearing arrangements are more sensitive to dynamic forces. The impulse nature of Pelton wheel jet impact also produces different vibration characteristics compared to reaction turbines like Francis and Kaplan.

What should I do if vibration reaches Zone C on a hydro turbine?

Zone C indicates the machine is not suitable for continuous long-term operation. Investigate root causes including runner cavitation, draft tube surge, guide bearing wear, shaft misalignment, or hydraulic resonance. Increase monitoring frequency, plan corrective maintenance during the next scheduled outage, and consider load restrictions.

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振動限值 — 水輪機與泵組

依據 ISO 20816-5 評估水輪機、水泵水輪機及泵的振動嚴重度。支援軸承座速度與軸位移測量。

ISO 20816-5 A/B/C/D 區水力機械

結果

振動區

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測量值

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建議

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公差帶	邊界	說明

ISO 20816-5 範圍

ISO 20816-5 規定了用於水力發電廠的水力機械（包括卡普蘭、法蘭西斯及培頓渦輪機、水泵水輪機和泵）的振動評估標準。涵蓋豎軸與臥軸機組配置。

軸承座振動 — 豎軸機組

在軸承座上測量的寬頻振動速度，單位為 mm/s RMS，通常為 10–1000 Hz 範圍。適用於垂直卡普蘭、法蘭西斯、泵-渦輪機及泵單元。此頁面上的分區邊界值為 ISO 10816/20816 系列的簡化指導值；ISO 20816-5 的機組及轉速特定表格在細節上有所不同，合約或驗收評估應參考該表格。

區域邊界	振速 (mm/s RMS)
A/B	2.8
B/C	5.3
C/D	8.5

軸承座振動 — 臥軸培頓

由於軸承配置與衝擊負載特性，臥軸培頓渦輪機的允許限值較低。

區域邊界	振速 (mm/s RMS)
A/B	2.3
B/C	4.5
C/D	7.1

軸位移 — 豎軸機組

軸相對位移使用近接探頭測量，以 μm 為單位的峰峰值位移表示。

區域邊界	位移 (μm p-p)
A/B	80
B/C	160
C/D	260

ℹ️ 注意： 由於重力沿軸向作用，豎軸水力機械具有獨特的振動特性。推力軸承狀態與水力作用力（尾水管湧浪、空蝕）顯著影響振動行為。

⚠️ 重要： 應同時監測軸承座與軸的振動。兩者評估中較差者決定整體評估結果。運轉條件（負載、水頭、尾水位）對水力機械的振動水平有強烈影響。