24V DC Axial Fan for Control Cabinet Cooling: 251.8 CFM

What the automation OEM needed

An industrial automation OEM specified a 172mm DC axial fan for a new range of control cabinets.

The enquiry arrived as a request for a formal specification sheet, with the part number already named. That is a familiar pattern. In practice it means the thermal model and the layout are both finished. Consequently the engineer is now collecting documents for design-in sign-off.

The fixed points

• First, the cabinet runs a 24 VDC internal rail, so the fan had to run from it directly.
• Next, the envelope was locked at 172 by 172 by 51 mm, a standard high-flow cabinet size.
• Free-air delivery had to reach roughly 250 CFM to carry the heat from VFDs, PLCs and power supplies.
• Ambient conditions ranged from -10C to +60C, since these cabinets go into unheated warehouses as well as factory floors.
• Finally, dual ball bearings were mandatory for service life.

Their market is global, so CE marking under the European LVD and EMC directives was not negotiable either.

Choosing the right DC axial fan variant

Here the customer had picked the right part. Even so, we checked the neighbouring options first, since a specification sheet is easy to send and expensive to get wrong.

AC never entered the discussion

The whole system architecture sits on a 24 VDC bus. Meanwhile an AC fan would need an inverter, which means another component, more cost and one more thing to fail inside an enclosure.

Three variants of the same frame

Our LWAD17251 DC axial fan series comes in several speed ratings inside the same 172mm body. Three of them mattered here.

• On one hand the high speed build reaches nearly 300 CFM. However, it also makes 72 dBA, which is far too loud beside a work area.
• The low-medium build runs at a comfortable 57 dBA, yet it only delivers 198.2 CFM. That misses the heat load.
• The medium-high build sits between them at 251.8 CFM and 64 dBA, drawing 31.2 W at 3800 RPM.

So the middle variant won. Specifically, it clears the airflow target, stays inside workplace noise limits and keeps the power budget sensible. By contrast, neither neighbour manages all three.

Materials that matter in an enclosure

Firstly, the die-cast aluminum frame holds the fan square and pulls heat from the motor stator. Meanwhile the PBT impeller carries a UL94V-0 flammability rating. Inside an electrical cabinet that matters far more than it does in open air.

That dual ball bearing choice supports the 50,000-hour rated life. A sleeve bearing would have cost less, yet it would not have lasted.

Technical Specifications

Read the noise figure alongside the airflow figure. In fact those two rows are where the variant choice was made.

Technical Documentation

Meanwhile the project image shows the initial customer selection from the LWAD17251 series overview, highlighting the specific performance targets.

Open Full Technical Specification (PDF)

The complete technical specification sheet contains all electrical and mechanical parameters, performance curves, and dimensional drawings required by design engineers for system integration.

Why the OEM designed us in

For a standard DC axial fan, the engineering is only half the decision. Meanwhile supply and paperwork make up the other half.

• Price against performance. This DC axial fan matches German catalog products on reliability figures, including the 50,000-hour L10 life, at a materially lower unit price. On equipment built at scale, that lands directly on the bill of materials.
• Shorter lead times. Our standard make-to-order lead time runs 15 to 25 days. By contrast, European makers commonly quote 12 to 18 weeks. Consequently the OEM can hold less inventory and still answer demand swings.
• Compliance without chasing. The fan ships CE marked as standard, and the documentation went out within one working day. Our China-local TUV NORD relationship keeps those certificates current rather than theoretical.
• Volume behind the part. Manufacturing here since 1990, with over 120,000 data center cooling units built annually, means this fan comes off a mature line. Batch-to-batch consistency follows from that, not from inspection alone.

Browse the axial fan range, or the DC axial fan section. Enclosure safety follows IEC 61439.

Questions about this fan

What control options exist for this model?

Here the standard build is a two-wire DC axial fan running at a fixed 3800 RPM from 24 VDC. Where variable speed is needed, the same series offers three-wire versions with tachometer output and four-wire versions with a PWM input. Either can be ordered against your control requirement.

What is the lead time for 500 units?

A make-to-order run of this size takes 15 to 25 days from purchase order to ex-works Ningbo. That covers scheduling, assembly and in-line performance testing on every unit. Customers with a frame agreement and rolling forecast can draw on regional stock and ship in 1 to 5 days instead.

Can it be mounted in any orientation?

Yes, because it uses dual ball bearings. Sleeve bearings often fail early when mounted vertically, since they rely on a lubricant film that gravity disturbs. Meanwhile ball bearings carry both axial and radial loads, so orientation makes no difference to the rated life.

Is 64 dBA loud for a cabinet fan?

It is noticeable, though it sits well inside typical workplace exposure limits for an industrial space. The honest trade-off is this: moving 250 CFM through a 172mm frame simply makes noise. So if a quieter cabinet matters more than airflow, the answer is usually a larger fan turning slower, rather than a quieter version of the same one.