了解原位動平衡校正
原位動平衡校正 — 源自拉丁語 原位，“在原地” — 是指 動平衡校正 a 轉子 轉子仍安裝在其原機中，位於正常運轉位置，並處於實際運轉條件下。工程師也稱此活動為 現場動平衡、現場動平衡或原位動平衡。與其將轉子拆下並運送至車間 動平衡機，技術人員會攜帶便攜式振動與相位測量設備至機台，並校正 不平衡 無需拆解。
1. 定義：原位動平衡的意義
原位動平衡的特徵在於轉子從未與其運轉的實際環境脫離。車間動平衡機在柔軟、經校準的軸承中旋轉裸露的轉子；原位作業則在真實的 軸承系統中，於真實基礎上，由真實原動機驅動，旋轉同一轉子。校正配重在組裝好的機台上計算並安裝，結果在運轉速度下驗證。這就是為何原位動平衡已成為大多數安裝工業機械（風機、鼓風機、泵浦、馬達、破碎機及類似旋轉設備）的預設方法。
2. 原位動平衡的優勢
此方法在現場實務中佔主導地位，因其兼具實務與技術效益。
無需拆解
由於轉子保持原位，此作業消除了拆解與重建機台的人力、拆除/運輸/重新安裝期間的損壞風險、將轉子運送至車間所耗費的天數或週數，以及重新組裝時引入新故障（ 不對心、鎖緊扭矩不正確、配合受損）的機會。
在實際運轉條件下進行動平衡
這是單一最重要的技術優勢，且是車間設備無法複製的：
- 實際軸承剛性： 真實軸承及其安裝剛性決定轉子對不平衡的響應，該響應可能與理想化的車間支撐顯著不同。
- 基礎與支撐效應： 底座、機架與安裝結構的柔性會塑造振動，這些效應會自動納入原位結果中。
- 運轉溫度： 熱膨脹及其對軸承游隙的影響在服務中存在，但在冷態車間中不存在，且可能改變轉子的平衡狀態。
- 工藝負載： 對於泵浦與風機，僅在負載下存在的 液壓 與 氣動力 會影響轉子的運轉方式。
- 組裝配合與游隙： 聯軸器、鍵與組件在最終組裝中的精確配合方式會影響平衡，原位方法可直接捕捉此效應。
簡言之，原位動平衡在轉子將要運轉的實際條件下校正轉子，包括動平衡機無法察覺的效應。
減少停機時間、降低成本、立即驗證
原位作業通常數小時內完成，而車間動平衡（拆除、運輸、動平衡、重新安裝）可能耗費數天或數週。對於關鍵生產設備，節省的時間直接轉化為產出與營收。消除運輸、車間人力與拆解也使大多數應用顯著降低成本。且由於 校正配重 安裝後，結果在現場真實條件下驗證；若需進一步微調，可立即進行，無需第二次拆解。
3. 原位動平衡最適用時機
此技術廣泛適用，但對以下情況特別具說服力：
- 大型機械： 難以或耗資龐大拆解與移動的大型風機、鼓風機與破碎機。
- 永久安裝轉子： 在原地組裝且從未設計為易於拆除的總成。
- 現場設備： 位於偏遠地點、運送至車間不切實際的機台。
- 緊急維修： 快速週轉對恢復生產至關重要的情況。
- Routine maintenance: periodic re-balancing to correct unbalance from 磨損, product build-up or erosion.
- Custom or non-standard equipment: rotors that simply will not fit standard shop machines.
4. The In-Situ Balancing Process
該流程遵循標準 影響係數法, adapted to the field environment. It is an iterative measure-correct-verify loop.
- Step 1 — Initial assessment: confirm that unbalance really is the dominant problem. Rule out faults that mimic it, such as misalignment, 鬆動 與 軸承缺陷; a pure unbalance shows a strong, stable 1× 運轉速度 component with steady 相位.
- Step 2 — Install sensors: 機腳 加速規 on the bearing housings with magnets, studs or adhesive, and fit a tachometer or 鍵相器 to supply the once-per-revolution phase reference.
- Step 3 — Initial run: run the machine at its normal operating speed and record the baseline 1× 振幅 and phase vectors.
- Step 4 — Trial-weight runs: 執行一次或多次 試重 runs as the chosen method demands — one for 單平面, more for 雙平面 運作。
- Step 5 — Calculate and fit corrections: the instrument computes the required correction masses and angles; they are then installed permanently by adding material (weld-on patches, bolt-on masses, set-screw weights) or removing it (drilling, grinding).
- Step 6 — Verification: run a final 驗證運轉 to confirm the residual vibration sits within the target acceptance band.
5. Equipment for In-Situ Balancing
Modern portable instruments are what made in-situ balancing routine and accessible. A complete field kit comprises a portable balancing instrument that fuses vibration measurement, phase detection and balancing computation into one battery-powered package; accelerometers with magnetic bases for quick attachment and removal; an optical or magnetic tachometer for the phase reference; and a weight kit of clamp-on, bolt-on and adhesive masses for both trial and permanent corrections.
Balanset-1A is a representative example: a two-channel device that reads 1× amplitude and phase at both bearings, computes the 影響係數 of the rotor, solves single- and two-plane corrections, and verifies the final 剩餘不平衡 against an ISO 21940-11 grade — all in the machine’s own bearings at operating speed. To plan the work, the free 試重計算器 sizes a safe first trial mass, and the 校正質量分解 tool splits a calculated correction onto the fixed holes or blades you actually have to work with.
6. Challenges and Considerations
For all its advantages, in-situ balancing brings field-specific complications:
- Access to correction planes: the planes must be reachable with the machine assembled; guards or covers sometimes have to come off to reach a balancing surface.
- Environmental factors: temperature extremes, dirt, noise and vibration carried in from nearby equipment all make field measurements harder than those in a controlled shop.
- 安全性： working on running machinery demands strict protocols — trial weights must be positively secured, and everyone must keep clear of rotating parts.
- Underlying mechanical faults: 軟腳, misalignment or loose mounts must be fixed before balancing, and in-situ conditions can make such faults harder to spot.
- Limits for extreme precision: for the tightest tolerances — precision grinders, high-speed spindles — dedicated shop machines may still be preferable, or used in combination with an in-situ trim.
7. In-Situ vs. Shop Balancing
The trade-off between the two approaches is best seen side by side:
| 方面 | 原位動平衡校正 | 車間動平衡校正 |
|---|---|---|
| 需要拆解 | 否 | 是 |
| 運轉條件 | 實際條件 | Idealised conditions |
| 週轉時間 | 小時 | 數天至數週 |
| 成本 | 較低 | 較高 |
| 精密 | 良好 | 優異 |
| 適用性 | 大多數機器 | 小型至中型轉子 |
The two are complementary rather than rival: a new rotor is often shop-balanced to a tight grade, then trimmed in situ once installed to absorb the assembly, foundation and thermal effects the shop could not see.
8. Industry Standards and Best Practices
In-situ balancing is formally recognised by international standards. ISO 21940-13 sets out the criteria and safeguards for the in-situ balancing of medium and large rotors, while the parent ISO 21940-11 （作為久經考驗的 ISO 1940-1）的現代繼承者，定義了平衡品質等級與允許的 公差 the work is judged against. Acceptance is frequently cross-checked against vibration-severity limits in the ISO 20816 系列中的振動嚴重度限值進行交叉核對。遵循這些標準，才能確保現場動平衡在每一次作業中皆能安全、有效且保持一致。
