FN24B3 Compact PLC Controller: Advanced Industrial Automation Solution
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What is the Comair Rotron FN24B3 fan?
The FN24B3 is Comair Rotron's FLIGHT® II DC axial fan — a 120 × 120 × 38 mm 24 V DC fan built for electronics enclosures, with PTC and polarity protection factory-fitted. The hub label reads the full identity: COMAIR ROTRON, FLIGHT® II DC, FS24B3 031157, MODEL FN24B3, 24 VDC .15 A 3.6 W, T JUN 17 04 (June 2004 date code), RED + BLACK, ASSEMBLED IN MEXICO, with the U.S. patent numbers 4779069 / 4494028 / 4633110 / 4779330 and the TÜV Rheinland, SA and CE marks. This listing's original title called it a PLC controller; the photographed hardware corrects that — it is a cooling fan. This record is a lot of four fans, new as recorded at intake on 31 December 2025. All eight photos and the inspection video show these exact fans.
Part details
| Field | Value |
|---|---|
| Brand | Comair Rotron — FLIGHT® II DC series, ASSEMBLED IN MEXICO |
| Model | FN24B3 (part ref FS24B3 031157), 120 × 120 × 38 mm axial fan |
| Rating | 24 V DC, 0.15 A, 3.6 W (hub label) |
| Protection | PTC & polarity protected (label); red + black two-lead free ends |
| Date code | T JUN 17 04 (June 2004); U.S. PAT. 4779069, 4494028, 4633110, 4779330 |
| Certifications | TÜV Rheinland, SA, CE |
| Construction | Seven-blade rotor, ball-bearing hub with brass collar, four corner mounts |
| Quantity | 4 fans, new as recorded, intake 31 December 2025 |
Values are read from the hub label and the photographed construction in the photo set.
Why the FLIGHT II held its slot for decades
Comair Rotron's FLIGHT II is the fan behind a generation of telecom power shelves and industrial enclosures, and the FN24B3's label shows why. The two protections printed on the hub — PTC and polarity — are the failure modes that kill cheap fans in the field: a stalled rotor that burns the winding, and an installer who lands the leads backwards. The PTC limits the current when the rotor locks; the polarity protection makes the reversed-lead mistake a no-event. At 3.6 W the fan is a rounding error on any 24 V rail, and the ball-bearing hub with its brass collar is built for the continuous duty those enclosures run.
The four fans in this lot are same-date-code stock — all four labels read T JUN 17 04, June 2004 — which matters for a fan swap: identical aero, identical current draw, identical mounting behaviour. They arrived new in their red-and-black free-lead format, ready for a terminal strip, and the wide photo shows the matching four side by side. For a cabinet whose original FLIGHT II has seized after years of service, these are the letter-of-the-part replacement.
Photos
All images below are original KOEED warehouse photos. Click any photo to view it full size.
For the same format from a different maker, see the Y.S. TECH FD124028EB-P — the 40 mm tach-equipped fan documented from the same warehouse.
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