Choosing between an eccentric eddy current separator and a concentric one comes down to one question: how fine is your non-ferrous fraction? For material above 20 mm, a concentric rotor delivers the same aluminum recovery at 20–30% lower purchase cost. Below 20 mm — and especially below 10 mm — an eccentric rotor recovers 10–15 percentage points more metal and cuts belt wear enough to pay back its premium within the first year. This article explains how each eddy current rotor design works, where each one wins, and gives you a decision table you can apply to your own material stream.
If you are new to the technology itself, start with our complete 와전류 분리 장치 가이드 covering working principle, operating parameters, and specifications — then come back here for the rotor decision.
What the Eddy Current Rotor Actually Does
The eddy current separator rotor is a drum fitted with alternating rare-earth (NdFeB) magnetic poles, spinning at 2,000–5,000 RPM inside a separate non-magnetic shell that carries the conveyor belt. The spinning poles create a rapidly alternating magnetic field at the head of the belt. Conductive non-ferrous metals passing through this field develop internal eddy currents, which generate an opposing field that throws the metal forward off the belt — while plastics, glass, and other inert material fall straight down.
Both rotor designs use this same physics. The difference is where the magnetic rotor sits inside the shell, and that single geometric choice changes the field shape, the belt temperature, the fine-particle recovery, and the maintenance bill.
Concentric Rotor: The High-Throughput Workhorse
In a concentric design, the magnetic rotor is centered inside the shell drum, so the field is present around the full circumference of the head pulley. The result is a wide, symmetrical separation zone that is forgiving of feed variations — burden depth, particle shape, and moisture can all drift without collapsing recovery.
Strengths:
- Lower cost — simpler rotor construction typically prices 20–30% below an equivalent-width eccentric unit
- High throughput on coarse material — the wide field zone handles 20–150 mm particles at up to 25 t/h on a 2,000 mm belt
- Simple maintenance — fewer adjustment points; any competent plant electrician can service it
Limits:
- Belt heating — because the field wraps the whole pulley, any stray ferrous particle that reaches the head is held against the belt and heated by induction. Over months this burns pinholes and grooves into the belt, the single most common concentric ECS maintenance cost.
- Weak surface field for fines — the field must reach through the full shell clearance, so flux density at the belt surface is lower. Particles under 10–15 mm receive too little repulsive force and drop into the reject stream.
Eccentric Rotor: Built for Fine Aluminum
In an eccentric design, the magnetic rotor is offset inside the shell and positioned only in the throw quadrant — the last section of belt travel where separation actually happens. All the magnetic energy concentrates into one small, intense zone exactly where particles leave the belt.
Strengths:
- Fine-particle recovery down to 3–5 mm — surface flux density in the separation zone is far higher, so small aluminum pieces that a concentric rotor drops are thrown cleanly into the product bin
- Dramatically lower belt wear — ferrous stragglers pass most of the pulley circumference outside the field, so they release instead of being pinned and induction-heated against the belt
- Adjustable pole position — the rotor angle can be rotated to move the throw point, letting commissioning engineers tune trajectory for each material instead of only adjusting the splitter
Limits:
- Higher purchase price — the offset rotor, adjustment mechanism, and reinforced bearings add 20–30% to the machine cost
- Narrower sweet spot — the concentrated zone assumes a thin, well-screened feed layer; throw a mixed 5–100 mm stream at it and coarse pieces will over-fly the splitter while the settings chase the fines
Eccentric vs Concentric: Side-by-Side
| 요인 | Concentric Rotor | Eccentric Rotor |
|---|---|---|
| Magnetic field zone | Full pulley circumference | Concentrated throw quadrant only |
| Effective particle size | 20–150 mm | 3–40 mm (best under 20 mm) |
| Aluminum recovery, 20–50 mm feed | 93–97% | 93–97% (no advantage) |
| Aluminum recovery, 5–10 mm feed | 65–78% | 80–90% |
| Belt wear from trapped ferrous | 고 — 주요 유지보수 비용 | 저 — 철제 재료가 필드 구역 밖으로 방출됨 |
| 포지션 조정 | 고정형 | 조절 가능한 투어 포인트 |
| 대비 구매 비용 | 기준선 | +20–30% |
| 일반적인 적용 사례 | MSW, C&D waste, ASR course fraction, UBC cans | IBA, zorba/zurik fines, WEEE, glass cullet, ASR fine fraction |
수리 수치는 현장에서의 패턴을 설명합니다: 두 설계가 잘 해방된 큰 스쿨프에서는 동일하게 성능을 보여줍니다. 따라서 동심 단위가 가격에서 승리합니다.
어느 루터가 알루미늄을 더 많이 회수하나요? 수치를 확인해보세요
이 두 설계를 비교하여 매번 구매자와 함께 설명하는 계산을 보여드립니다. 5–15 mm 범위의 2.5% 비철제 내용물을 가진 연소기 바닥죽을 처리하는 공장이 4,000 시간을 매년 운영하는 경우:
- 동심 단위는 72% 회수: 매년 576 톤의 비철제가 회수됩니다
- 이심단위는 86% 회수: 매년 688 톤
- 차이점: 매년 추가 금속 112 톤 — 일반적인 IBA 등급 알루미늄 가격 $1,100–1,400/톤, 매년 추가 수익은 123,000–157,000 $입니다
저가의 기계 프리미엄과 비교하여 이심 루터는 이 스트림에서 6개월 안에 회수되며, 벨트 교체를 피한 것을 포함하지 않습니다. 40 mm C&D 스트림에서 회수가 동일한 경우, 동심 단위를 구매하고 차이를 예금하세요.
파티클 크기 분포가 결과를 결정합니다. 구매 명령서를 체결하기 전에 자신의 분포를 측정하지 않았다면, 20 mm 분할로 대표 샘플을 스크린하고 각 분할의 금속을 무게를 측정하세요. 우리의 엔지니어는 고객 샘플을 무료로 이 분석을 수행합니다 미세 알루미늄 ECS trials.
선정 체크리스트
- Feed mostly above 20 mm? Concentric. The recovery is identical and the machine costs less.
- Meaningful metal value below 15 mm? Eccentric — or a two-stage line with a concentric unit on the coarse screen fraction and an eccentric unit on the fines.
- Poor upstream ferrous removal? Lean eccentric to protect the belt, but fix the real problem: install or upgrade the 자기 분리기 ahead of the ECS.
- IBA, zorba, WEEE, or glass cullet? These streams are defined by fine, high-value metal — eccentric is the standard choice across the industry.
- Unsure? Send us a 50 kg sample. A test run on both rotor types settles the question with data instead of brochure claims.
자주 묻는 질문
concentric eddy current separator 를 eccentric으로 개조할 수 있나요?
No. The rotor position, shell geometry, bearing arrangement, and frame are different structures — there is no practical field conversion. If your material has shifted toward fines, the economic route is adding a dedicated eccentric unit on the screened fine fraction rather than replacing the existing concentric machine, which continues earning on the coarse fraction.
이상축 레이터가 다른 벨트가 필요한가요?
Both designs use similar PVC or PU conveyor belts, but the eccentric unit extends belt life significantly — often 2–3× — because trapped ferrous particles are not induction-heated against the belt surface. On concentric units in dirty streams, budget for belt replacement as a routine consumable.
도시 쓰레기 처리를 위한 적합한 설계는 무엇인가요?
For a standard MRF recovering aluminum cans and coarse non-ferrous from MSW, a concentric rotor is the cost-effective choice — can-sized material sits squarely in its 20–150 mm effective range. Plants that also process the fine screen underflow add an eccentric unit for that fraction.
두 설계의 레이터 속도 설정이 다릅니다か?
The operating logic is the same — finer material wants higher RPM — but eccentric units are typically run at the upper end (3,800–4,500 RPM) because they are deployed on fine fractions. See the operating-parameter section of our 와전류 분리 장치 가이드 for starting-point settings by particle size.
Get the Right Rotor for Your Material
The concentric vs eccentric decision is a particle-size decision, not a brand decision. Measure your size distribution, put a value on the metal in each fraction, and the right rotor selects itself. Energycle manufactures both designs in belt widths from 600 to 2,000 mm and tests customer material on real machines before quoting. Send us your material analysis — we will recommend a configuration and provide a detailed quotation within 48 hours.
