What is vibration velocity?

Vibration velocity is the speed at which a vibrating surface moves back and forth, measured in mm/s RMS. It is the most widely used parameter for evaluating machine condition because it correlates well with vibration energy and bearing/structural damage. ISO 10816 and ISO 20816 define permissible limits based on machine class.

ISO 10816 與 ISO 20816 有何不同？

ISO 20816 is the modern replacement for ISO 10816. The zone boundaries and machine classes are essentially the same for most non-rotating parts (housing) vibration evaluation. ISO 20816 adds shaft vibration requirements and updated measurement practices. For broadband velocity RMS evaluation on machine housings, the classic ISO 10816 limits still apply.

How do I measure vibration velocity?

Vibration velocity is measured with an accelerometer or velocity sensor mounted on the machine bearing housing. The sensor signal is processed by a vibration analyzer or portable instrument to produce a broadband RMS velocity value in mm/s. Measurements should be taken in three directions: horizontal, vertical, and axial.

What should I do if the machine is in Zone C or D?

Zone C means the vibration level is tolerable only for limited periods — plan corrective action. Zone D means the vibration is severe enough to cause damage — stop the machine immediately if possible and investigate root cause. Common corrective actions include re-balancing, alignment correction, bearing replacement, or addressing structural resonance.

Which sensor is best for vibration velocity measurement?

For most industrial machines, a piezoelectric accelerometer with integrated electronics (IEPE/ICP type) is the standard choice. The acceleration signal is electronically integrated to velocity. For low-frequency applications below 10 Hz, electrodynamic velocity sensors may be preferred. Ensure the sensor frequency range covers 10-1000 Hz per ISO 10816.

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允許振動速度 (ISO 10816)

查詢 ISO 10816 / ISO 20816 的允許振動速度限值。選擇機組類別，輸入測得速度以取得 A/B/C/D 區間評估。

ISO 10816 ISO 20816 A / B / C / D 區間

結果

區間評估

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機組類別

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量測速度

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等效值 (in/s)

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公差帶	速度範圍	意義

振動速度 RMS

振動速度 RMS 值與峰值速度的關係為：

v_RMS — 振動速度均方根值 (mm/s)
v_峰值 — 振動速度峰值 (mm/s)

ISO 10816 根據寬頻振_RMS (通常為 10–1000 Hz) 評估機組振動嚴重度。機組分為四類，每類有四個評估區間 (A、B、C、D)。

ISO 10816 區間界限 — 所有類別

公差帶	第一類 (≤15 kW)	第二類 (15–75 kW)	第三類 (剛性, >75 kW)	第四類 (柔性, 渦輪機)
A (新機)	≤ 0.71	≤ 1.12	≤ 1.8	≤ 2.8
B (可接受)	0.71 – 1.8	1.12 – 2.8	1.8 – 4.5	2.8 – 7.1
C (可容忍)	1.8 – 4.5	2.8 – 7.1	4.5 – 11.2	7.1 – 18
D (具破壞性)	> 4.5	> 7.1	> 11.2	> 18

所有數值均為 mm/s RMS。

實務範例

範例 — 45 kW 馬達 (II 類)

已知： 測得振動速度 = 3.2 mm/s RMS

II 類邊界：A ≤ 1.12，B ≤ 2.8，C ≤ 7.1，D > 7.1

3.2 mm/s 超過 B 邊界 (2.8)，但低於 C 邊界 (7.1)

結果： C 區 — 僅限短期可接受。請規劃校正措施。

ISO 10816 振動速度限值 — 區域計算器

結果

振動速度 RMS

ISO 10816 區間界限 — 所有類別

實務範例

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