What machines does ISO 20816-2 cover?

ISO 20816-2 applies to steam turbines and generators with power output greater than 40 MW and operating speeds between 1500 and 3600 RPM. This includes large power station turbine-generator sets, industrial steam turbines, and combined-cycle plant generators.

What is the difference between bearing housing and shaft relative measurement?

Bearing housing vibration is measured with accelerometers or velocity sensors mounted on the bearing cap, expressed in mm/s RMS. Shaft relative vibration is measured with proximity probes installed inside the bearing, measuring shaft displacement relative to the bearing, expressed in μm peak-to-peak. Both should be monitored for a complete picture.

Why are shaft vibration limits important for steam turbines?

Steam turbines use fluid-film (journal) bearings where the bearing housing may not vibrate significantly even when the shaft has high vibration. Shaft relative measurement captures the actual rotor dynamic behavior, detecting issues like unbalance, misalignment, oil whirl, and rotor cracks that bearing housing sensors might miss.

What should I do if vibration reaches Zone C?

For Zone C on steam turbines: investigate the root cause immediately, increase monitoring frequency, plan corrective action during the next scheduled outage, inform plant management. The turbine may continue operating for a limited period but should not remain in Zone C indefinitely. Common causes include unbalance, misalignment, bearing wear, and thermal bowing.

How does ISO 20816-2 relate to ISO 7919-2?

ISO 20816-2 consolidates the content of the former ISO 10816-2 (bearing housing vibration) and ISO 7919-2 (shaft vibration) into a single standard. It covers both measurement types with updated guidance and zone boundaries for steam turbines and generators.

免費工程工具 #020

振動限值 — 汽輪機與發電機 >40 MW

依據 ISO 20816-2 評估汽輪機與發電機的振動嚴重度。支援軸承座速度與軸相對位移量測。

ISO 20816-2 A/B/C/D 區 >40 MW

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 20816-2 範圍

ISO 20816-2 規範了輸出超過 40 MW、運轉速度介於 1500 至 3600 RPM（50/60 Hz 發電）之汽輪機與發電機的振動評估準則。涵蓋軸承座振動與軸相對振動。

軸承座振動

軸承座（基座）上測量的寬頻振動速度單位為 mm/s RMS，通常位於 10–1000 Hz 頻率範圍。以下邊界值對應於已發布表格中轉速為 1500 r/min 與 1800 r/min 的欄位；對於 3000–3600 r/min 機台，已發布的邊界值較高（A/B 3.8、B/C 7.5、C/D 11.8 mm/s RMS），因此此簡化單一表格對兩極機台而言屬保守估計。

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

軸相對位移

軸振動以近接探頭量測，以 μm 峰對峰值表示。這些數值為一般應用之簡化值。

區域邊界	位移 (μm p-p)
A/B	50
B/C	100
C/D	165

ℹ️ 注意： 軸位移限值可能隨運轉速度而異。上述數值為一般用途之簡化值。如需精確的速度相關限值，請參閱完整 ISO 20816-2 標準。

⚠️ 重要： 應同時監控軸承座與軸振動。機器可能顯示低軸承座振動但高軸振動，或反之。兩者評估中較差者決定整體評估結果。