What is an influence coefficient?

An influence coefficient describes how a unit weight at a specific location and angle affects the vibration of a rotor. It is a complex number (magnitude and phase) that relates the change in vibration to the trial weight that caused it. Once known, the coefficient can be used to calculate the exact correction weight needed.

How to do single-plane balancing?

Single-plane balancing involves three steps: 1) Measure initial vibration (amplitude and phase), 2) Add a known trial weight and measure the new vibration, 3) Use vector math to calculate the correction weight. The influence coefficient method automates step 3 by computing the vibration change vector and dividing to find the correction.

What if vibration increases after adding the trial weight?

An increase in vibration after adding the trial weight is normal and expected in many cases — it simply means the trial weight was placed in an unfavorable angular position. The vector math still works correctly regardless. However, if vibration increases dramatically (more than 3-4×), use a smaller trial weight for safety.

Can I do multiple runs to improve accuracy?

Yes. After placing the calculated correction weight, you can measure the residual vibration and perform another trim balance run using the same influence coefficient. Each iteration typically reduces residual vibration. Two to three runs usually achieve the desired balance quality.

What factors affect accuracy?

Key accuracy factors include: measurement repeatability (run the rotor to the same speed), sensor quality and mounting, phase reference stability, rotor thermal state consistency, and trial weight size (should produce a measurable change but not be dangerously large — typically 5-30% of the expected correction).

免費工程工具 — #010

影響係數計算器

使用影響係數法進行單平面轉子動平衡校正。輸入初始振動、試重資料，即可獲得精確的校正配重與角度。

單平面向量數學校正配重

初始振動（第 1 次運轉 — 無試重）

振幅 A₀ （mm/s、μm 或 mils）

相位 φ₀ （度）

試重

試重質量 m_t （g）

試重角度 θ_t （度）

加裝試重後的振動（第 2 次運轉）

振幅 A₁ （與 A₀ 單位相同）

相位 φ₁ （度）

校正半徑（選填）

校正半徑 R （mm — 僅供參考：計算出的校正質量適用於試重半徑）

快速預設

結果

校正配重

—

校正角度

—

影響係數 |C|

—

影響向量 ΔV

—

預估殘餘不平衡

—

振動向量

振動以帶有振幅與相位的複數向量表示：

影響向量

試重所引起的振動變化：

校正配重

校正配重透過複數除法計算：

ℹ️ 注意： 負號確保校正配重與不平衡方向相反。結果為一向量：模長表示以克為單位的重量，幅角表示角度位置。

實務範例

範例 — 單平面動平衡校正

已知： V₀ = 5∠45°，試重 = 10g@0°，V₁ = 8∠120°

ΔV = V₁ − V₀ = (8∠120°) − (5∠45°) = 複數減法

W_c = −m_t × V₀ / ΔV → 校正的模長與角度

⚠️ 重要： 在加裝校正配重前，務必先移除試重。校正配重將取代試重 — 切勿將兩者同時留在轉子上。