EC Centrifugal Blowers

What EC means for an OEM

An EC motor is a permanent-magnet brushless motor with its own drive board on the mains side. For a machine builder that changes four things.

• One part instead of three. No external inverter, no separate speed controller, no screened motor cable to specify, mount and get through your own EMC testing.
• Constant speed under load. The drive holds the set speed as filters load up or dampers close, so the duty point moves along the curve in a predictable way instead of drifting the way a tapped AC motor does.
• Step-less speed instead of fixed taps. Any speed between minimum and maximum, set from your own controller.
• Part-load energy. About 30% lower consumption at part load, confirmed against the load profile. The saving comes from running slower for most of the year, so it is only real if your machine actually spends its hours below full speed.

Control, feedback and protection

• 0-10 V or PWM speed input as standard. The 092-rotor units we checked take PWM at 1-10 kHz.
• RS485 on the 102, 138 and 188 rotor sizes, for setpoint and readback over a bus when several blowers sit in one machine. The rotor size is the second number in the model code, so the code tells you whether RS485 is available.
• FG tacho output for speed feedback into your controller. Pulses per revolution depend on the motor; the 138-rotor unit we checked gives 12 per revolution.
• Locked-rotor protection in the drive, and a wide mains window: 200-277 VAC on the 146 model rated 230 V.

The LWFE3G range at a glance

Airflow is at free delivery and static pressure is at closed outlet. They are the two ends of the family, never one operating point, so size from the curve of the individual model. Mains supply is 230 V single phase across the range, with 380 V on the larger dual-intake sizes. Catalogue design ratings run IP44 to IP54 with class B or F insulation by model; we hold no third-party IP certificate and do not claim one. Impellers are balanced to G6.3 and bearings are rated 20,000 h L10 at 70 °C on LWFE3G250-138DS-02.

Two worked examples: a 146 mm dual-intake unit at 230 V, 1450 rpm, 0.8 A, 115 W, 1009 m³/h, 670 Pa, 61 dB(A), about 4.5 kg; and a 250 mm dual-intake unit at 220 V, 960 rpm, 3.5 A, 750 W, 4017 m³/h, 479 Pa, 75 dB(A), about 15 kg. Model-level P-Q curves, dimensions and CAD are on our selection site. Cross-family comparison sits in the catalogue performance table on the centrifugal blower hub.

Where EC pays back, and where it does not

An EC blower costs more than the AC equivalent because you are buying the electronics with the motor. It earns that back when:

• the machine runs long hours and spends most of them below full speed;
• airflow has to stay constant as the filter loads, or has to follow a sensor;
• several blowers in one cabinet need to be set and read back over a bus;
• there is no panel space, no cable route and no budget for a separate inverter;
• the end user is buying on running cost or on an energy label rather than on unit price.

It does not pay back on single-speed duty at full load with short annual hours, or on price-driven builds where a two-speed AC motor already meets the spec. In those cases look at the AC single inlet blowers. For low-voltage 12/24/48 V supply, a DC brushless blower is usually the cheaper answer. Backward-curved EC plug fans and axial ranges are a different family and are not on this site; they sit on longwellfans.com.

How these blowers are built and checked

LONGWELL engineers and specifies this range. The blowers are built to LONGWELL drawings in qualified partner plants, inspected to LONGWELL standards, then labelled and shipped under LONGWELL. The full sourcing statement is on our home page, and the step-by-step OEM route from drawing to first shipment is at our OEM process.

What we run ourselves, in our own plant in Yuyao: automatic motor winding with coil insertion, inter-turn insulation testing, argon-arc welding of lead wires, rotor press-fit and magnetising, audited during the 2021 ETL factory audit. Our QC equipment includes dynamic balancing machines, an end-of-line electrical safety and run test covering earth continuity, dielectric withstand, insulation resistance and running current, a high and low temperature chamber, and ageing. Air performance is tested to the AMCA 210 method; sound work uses a semi-anechoic room, chamber 4.0 x 4.0 x 3.0 m, calibration report SSD202500326. More on the factory page.

Certification status, stated exactly

• Management systems: ISO 9001 BMCQ0222448M, ISO 14001 BMCE0222279M, ISO 45001 BMCS0222232M, valid to 8 December 2028.
• CE: our KTS (Shenzhen) CE certificates - LVD KB2207084L01, EMC KB2207085E01, RoHS KB2207086R01, issued 11 July 2022 - cover the AC forward-curved models LWFA108 to LWFA450 only. This EC family is outside that scope. If you need CE for an EC model, raise it at enquiry stage and we will agree the route with you.
• ETL: part of the EC centrifugal range is an ETL Recognized Component under Intertek control number 5022563. Coverage follows the model rules in the report, so ask us to confirm the model you have chosen.
• Air performance: tested to the AMCA 210 method.

Certificate numbers and scopes are listed on quality and certifications.

Samples, lead time and documents

Samples of catalogue models ship in 1-3 days. Production lead time is 15-30 days. Warranty is 12 months. For a quotation we need airflow and static pressure at your duty point, supply voltage, control signal, mounting and outlet orientation, annual volume and target price. Send a sketch or a 3D file and we will come back with the nearest catalogue model plus what a modified version would take.

Tell us your duty point and we will match an EC blower from the LWFE3G range. Request a quote.