showstack / glossary / phase-rotation
Phase rotation 相序
The order in which the three phases of a supply reach their peaks. Swapping any two conductors reverses it. Single-phase loads, dimmers and heaters are unaffected and give no indication, but a three-phase motor turns in whatever direction the field rotates, so a chain hoist on a reversed supply runs the opposite way to its controls. Checked with a rotation meter at every unfamiliar supply and after every adaptor, before anything is connected.
中文
三相電源各相到達峰值的先後次序。任意對調兩條相線即會反轉。單相負載、調光器與電熱負載完全 不受影響，也不會有任何徵兆；但三相馬達的旋轉方向取決於磁場旋轉方向，因此電動吊車接到相序 相反的電源時，動作方向會與控制器相反。每逢接觸陌生電源或經過轉接頭後，都必須先用相序表檢 查再接入設備。
Regional usage
| Where | Term | Note |
|---|---|---|
| UK | Phase rotation | |
| US | Phase sequence / phase rotation | |
| HK / TW | 相序 | Spoken as 相序; crews often just say "check the rotation" in English. |
Easy to get wrong
A rotation meter says nothing about voltage or earth quality. A correct rotation is not evidence of a sound supply, only of a correctly ordered one.
Next to this
Sources
- IEC 60364 and IEC 60038 low-voltage installation and supply standards — International Electrotechnical Commission primary
Understand the mechanism
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