When a Customer Asks for Silicone Potting by Name

What the AHU builder specified

An OEM building commercial HVAC systems needed a plug fan for a new air handling unit, with potted fan electronics specified. Peak airflow was 21,321 m3/h.

However, two requirements stood out, and neither was about airflow.

RS485, for closed-loop control

The fan needed built-in RS485 serial communication, so it could talk to a modern building management system directly.

That gives real closed-loop control. Namely airflow set from live sensor data, rather than from a fixed schedule. Efficiency targets under standards such as ASHRAE 90.1 effectively assume it.

Potted fan electronics, requested by name

Specifically, the customer asked for silicone thermal potting on the motor electronics. Frankly, nobody requests potted fan electronics casually.

It tells you the fan will live somewhere unkind, with damp, dust and shake all present. Evidently service life matters more here than what potted fan electronics cost to add.

Meanwhile the remaining limits followed from the application.

• Peak pressure of 963 Pa, since HEPA filters, deep coils and long ducts all resist.
• A compact plug-fan shape fitting an 800 by 800mm frame inside the plenum.
• Lastly, an ambient range from -40C to +80C, which is unusually wide.

Configuring the EC plug fan

Here the duty point runs over 21,000 m3/h at more than 900 Pa. Consequently the choice narrowed to our LWBE3G backward-curved series, built for high-pressure, high-efficiency work.

Why not AC with a drive

We considered an AC motor with a separate drive, then rejected it. It brings in a third-party part, a failure point, and extra integration work on the customer side.

Native RS485 was the deciding factor. Our integrated SmartEC platform already carries 0-10V, PWM and Modbus RTU, which simplifies the customer controls architecture instead of complicating it.

Why 630mm, and why plug

A 630mm impeller puts the customer duty point near peak efficiency on the curve, rather than at its edge. In short, that is where the energy saving comes from.

Choosing the plug-fan variant drops the scroll housing entirely. Consequently the footprint falls by nearly 40%, and the losses a scroll adds go with it. In modern AHU design, that pairing is hard to argue with.

Build details

The impeller is strong aluminum alloy, balanced to G6.3 per JB/T 9101-1999. That keeps shake low on a wheel this size.

So we used our standard silicone compound, fully sealing the SmartEC drive to reach IP54. Potted fan electronics answered the customer reliability worry directly, rather than roughly.

Meanwhile the -40C to +80C range comes from our ThermoFlex approach, pairing automotive-grade parts with heat management design. In the end one factory-validated product met every constraint.

Technical Specifications

The model number ends in -47, marking a factory-built variant of this EC plug fan. The questions at the end say exactly what that suffix covers.

Parameter	Value
Model	LWBE3G630-188PT-07-47
Motor Type	EC Backward Centrifugal Fan
Nominal Voltage	3~380 VAC
Voltage Range	380-480 VAC
Frequency	50/60 Hz
Rated Power	3350 W
Rated Current	3.6 A
Speed	1450 RPM
Max Air Flow	21321 m³/h / 12542 CFM
Max Static Pressure	963 Pa
Noise Level (LpA)	87 dB(A)
Protection Type	IP54
Insulation Class	Class F
Operating Temperature	-25°C to +60°C
Ambient Temperature Range	-40°C to +80°C
Life Expectancy (L10 @ 40°C)	40,000 Hours
Impeller Material	Aluminum Alloy
Control Interface	0-10VDC, RS485 (LWRS485-01 V2)
Certifications	CE, RoHS, Reach

Technical Documentation

Here the image shows the LWBE3G630-188PT-07 EC plug fan, a form factor designed for compact integration into air handling units. Procurement managers and system integrators can use this to visualize the final product.

Here the document contains the complete technical specifications, dimensional drawings, P-Q performance curves, and wiring diagrams for the LWBE3G630-188PT-07-47. It is the primary engineering deliverable for design and installation engineers.
Download the LWBE3G630-188PT-07 datasheet

Why the OEM specified our platform

On a project where reliability drove the specification, four things counted.

• A custom pairing inside one quarter. RS485 control plus silicone potting is a specific ask. Our in-house engineering and 90-day NPI process settled the spec and shipped tested samples in one quarter. European suppliers quote far longer for the same change.
• Lower total cost, not just a lower fan price. A built-in EC drive removed the need to buy, mount and qualify a separate VFD. That deletes a component, a panel position and a qualification exercise from the customer project, none of which ever appear on the fan line of a quotation.
• Compliance already in place. An outside lab checks the airflow data to AMCA 210/211 and ISO 5801, and the unit carries full CE marking. Consequently the customer own approval risk and timing both shrink.
• Built for places that cannot fail. A 40,000-hour L10 life and IP54 build suit jobs where failure is unacceptable. Furthermore we ship over 120,000 units a year into data centers and similar critical sectors.

Browse our EC plug fan range, or the AHU fan section. Modbus is published by the Modbus Organization.

Questions about the custom configuration

What does the -47 suffix mean?

It marks a factory-customized configuration. On this project it covers two things: activation and testing of the onboard RS485 Modbus RTU protocol through the SmartEC controller, and application of a high-grade silicone potting compound to the motor electronics, which lifts moisture and vibration resistance to meet IP54.

What voltage range does the motor accept?

Nominal is three-phase 380 VAC. The integrated SmartEC drive runs reliably anywhere from 380 to 480 VAC at 50 or 60 Hz. That wide window keeps performance stable through the voltage fluctuation common on industrial or remote grids, which protects the motor and holds airflow steady.

How is the 40,000-hour L10 figure derived?

From accelerated life testing of the maintenance-free deep groove ball bearings, conducted to ISO 281. It means that at a continuous 40C, 90% of a large sample is statistically projected to run at least that long without a bearing failure. That is over four and a half years of non-stop operation.

Why do potted fan electronics matter so much?

Because in an EC plug fan the drive electronics sit inside the motor, meeting the same heat, damp and shake. Potting seals them, so moisture cannot settle on a board and vibration cannot tire a solder joint. On a fan expected to run for years, that usually decides whether it reaches its design life.