A tiny fan with a big dependency
An industrial OEM needed an obsolete fan replacement for the 7 W axial unit that cools the condenser in their centrifuge line. The old part was fading from supply, and the assembly built around it could not change.
What they could provide was the part itself: specs and field images of the original, a 200mm blade in a 246mm ring-mount frame on 230 V.
The constraints the legacy part left behind
- First, the exact 246mm outer frame and mounting pitch, since the sheet metal tooling is frozen for good.
- Next, suction-side airflow drawing heat across the condenser coils, exactly as before.
- Meanwhile dual 50/60 Hz operation, so one chassis ships to Europe and North America alike.
- Finally, 1,000 to 2,000 units a year, at industrial IP levels for dust and incidental moisture.
Why a 7 W part carries so much weight
The fan is trivial next to the centrifuge it cools, and that is exactly the trap. After all, a vanished minor part stops the same production line a vanished major one does.
Obsolescence does not scale with price. Rather, it scales with how deeply the part is designed in.
Obsolete fan replacement from evidence
An obsolete fan replacement is a spec built backwards. The original maker cannot be asked, so the part and its setting must answer instead.
What the evidence had to establish
Dimensions are the easy layer. For instance, frame, blade diameter, depth and the ring-mount interface all measure directly.
Meanwhile the working layer is quieter: which way the air flows against the mounting face, speed on both 50 and 60 Hz, the real duty point next to the coil, and how the 7 W draw splits between moving air and enduring heat. Those come from measuring and from reading the setting, not from a card in a catalog.
Why AC stayed
We reviewed an EC option and set it aside without drama. The equipment offers plain mains, the duty is fixed, and at 7 W the efficiency gap cannot repay added electronics across even 2,000 units a year.
In fact, the dual-frequency requirement decided more than the motor debate did. The winding must give good airflow at both grid speeds, because the OEM ships one build worldwide and the fan cannot be the reason regional variants exist.
The ring mount detail
Here the legacy ring mount pairs the fan to the condenser at a set distance and angle. So reproducing the mount reproduces the aerodynamic setting, which is why we treated the ring dimensions as performance parameters rather than bracket trivia.
Verification against the survivor
We proved the obsolete fan replacement side by side with a working old unit: airflow, current, noise and heat rise at both frequencies.
In the end, that comparison, not the rebuilt drawing, is the acceptance evidence. The drawing says what we believe, while the survivor says what the machine has been living with. Airflow methods follow ISO 5801.
Technical Specifications
Every row below was reconstructed from the legacy unit and then verified, because the original maker no longer answers.
| Parameter | Value |
|---|---|
| Model Number | LWAA4E200S-5MEW-45-00 |
| Voltage | 220 VAC |
| Frequency | 50/60 Hz |
| Power | 7 W |
| Speed | 1300 ± 100 RPM |
| Impeller Diameter | 200 mm |
| Outer Frame Diameter | 246 ± 2 mm |
| Mounting Hole PCD | 236 mm (4 x Ø4.3 mm) |
| Motor Depth | 69 ± 1.5 mm |
| Impeller Depth | 49 ± 1.5 mm |
| Lead Wire Length (L) | 475 ± 15 mm |
| Impeller Material | Aluminum |
| Frame Material | Iron |
| Airflow Direction | Suction (S) |
Technical Documentation
longwell–spec-sheet-01.pdf
The mechanical drawing provides dimensional tolerances, material callouts, and mounting pitch data required by mechanical engineers verifying chassis fitment.
Here the input document captures the OEM’s original technical requirements, including the 230V voltage and 200mm blade constraints.
This visual reference shows the final assembly structure, highlighting the five-blade aluminum impeller and integrated iron mounting ring.
Running your own replacement hunt
Obsolete fan replacement projects follow a pattern. Four moves make yours shorter.
- Send the real part, working if possible. An obsolete fan replacement built from photos guesses at everything a caliper and a bench answer directly. A surviving unit is the single most valuable object in the project, so ship one.
- Capture the installation, not just the fan. Mounting distance to the coil, airflow direction and the box around them are part of the performance. So photograph the fan in place before removing it, from angles that show what it faces.
- Test candidates at your real frequencies and voltages. A replacement matched at 50 Hz can disappoint at 60. Hence, if your equipment ships to both grids, testing at both is part of what fit means.
- Start before the last supplier stops. The cheapest replacement project begins while original units and stock still exist to measure against. By contrast, the priciest one begins after the final failure, with the line down and the evidence in a bin.
See our axial fans range, the AC axial fans section, or condenser fans.
Questions about legacy replacements
How exact does a replacement have to be?
Exact where the machine touches it: the mount, the envelope, the airflow direction and the air delivered at the duty point. Free elsewhere. The skill lies in knowing which dimensions bind and which do not, and the setting, not the old datasheet, decides that.
What if no working original survives?
The project gets harder but not hopeless. Dimensions come from dead units, and you bracket the performance from the coil size, the heat rise and the equipment ratings. So expect a wider validation program, since the target is rebuilt rather than measured.
Why not redesign the equipment around a current standard fan?
At some volume that is the right call, but it costs design work, fresh approvals and change control across the product. The replacement path keeps all of that intact. The honest comparison prices both, which is the same arithmetic as any tooling decision.
Can one replacement serve both 50 and 60 Hz markets?
Yes, if you design it to. The same motor runs about 20% faster on 60 Hz, moving more air and drawing more power. Therefore the winding and blade choice must keep both operating points acceptable, which is why testing at both frequencies belongs in acceptance.
Technical Documentation & Resources
Need the same thing for your own unit?
Give us the numbers and the envelope, and you get a shortlist rather than a catalog. Meanwhile custom spec sheets and samples run to 90 days. Since 1990 Longwell has supplied EC fans and blowers to OEMs in HVAC, cold chain, data center and industrial markets.
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