FB3G250-24PL-90 DC Backward Centrifugal Fan, 24VDC, 250mm, 1124.5 m3/h

Brief Description

The FB3G250-24PL-90 is a 24VDC ultra-quiet DC backward centrifugal fan that delivers whisper-level operation at just 69 dB(A) — below normal conversation volume — while generating 1124.5 m³/h airflow at 420 Pa static pressure. Drawing only 72W from a standard 24V battery or solar power system, it achieves an exceptional balance of acoustic comfort, energy efficiency, and reliable performance. The BLDC92 brushless motor operates across a wide 16-28 VDC input range, making it ideal for variable battery states in off-grid and mobile applications. At its heart, a precision backward curved impeller paired with an integrated FG tach output provides real-time speed feedback at 2050 RPM, compatible with 0-10VDC and PWM control for seamless automation integration. With IP44-rated ingress protection, Class B insulation, and a 50,000-hour L10 service life, this 250mm fan is purpose-built for noise-sensitive environments requiring dependable DC ventilation. Ideal applications include medical equipment cooling, laboratory fume extraction, office HVAC, residential energy-recovery ventilators, battery storage enclosure ventilation, and mobile shelter climate control. CE and RoHS certified.

Product Specification

At the core of the FB3G250-24PL-90 is a BLDC92 external rotor brushless DC motor driving a backward curved centrifugal impeller with a 250mm diameter, optimized for low-noise operation at 2050 RPM. The aerodynamic design achieves 75-80% efficiency, converting just 72W of DC power into 1124.5 m³/h of airflow at up to 420 Pa static pressure — delivering whisper-quiet 69 dB(A) operation while cutting energy consumption by 30-40% compared to equivalent AC fans. Its wide 16-28 VDC input range with only 3.0A current draw ensures stable performance across battery discharge cycles, making it suitable for 24V solar-direct, battery-buffered, and vehicle-mounted DC systems. The comprehensive control interface accepts 0-10VDC analog signals and PWM (1-10kHz) digital inputs for stepless speed regulation, while the FG tachometer output delivers real-time RPM feedback for closed-loop integration with PLC, microcontroller, or building management systems. Built-in protection features include soft-start, current limiting, locked-rotor protection, and reverse polarity protection on the DC input. The fan construction features a die-cast aluminum housing with IP44-rated sealing against water splashes and solid objects larger than 1mm. Ball bearings permit any mounting orientation, and Class B electrical insulation supports safe operation in ambient temperatures up to 130°C. Rated for 50,000 hours L10 lifespan at 40°C ambient with minimal maintenance owing to the brushless motor design, this fan is engineered for applications where silent operation, low power draw, and DC compatibility are non-negotiable requirements.

Nominal Date

DC Backward Centrifugal Fan
Type	FB3G250-24PL-90
Model	BLDC92

Connection diagram

Remarks:

I. Standard lead wire length is 300mm; customized length available upon request.

II. Control via 0-10VDC analog signal or PWM digital signal.

Product drawing

Aerodynamic Performance Charts

Test condition:

I. Measurement performed according to ISO 5801, using double chamber method.

II. Test voltage: 24VDC, ambient temperature: 23±2°C, relative humidity: 50±10%.

III. Noise measured at 1m distance in anechoic chamber per ISO 3744.

IV. PQ curve shows performance across 0-100% duty cycle at rated voltage.

Safety Requirements

I. When taking out the fan, do not directly lift the fan lead wire. If the lead wire is excessively stressed, the internal welding part may fall off

II. Do not plug or unplug the fan lead plug when the fan is running

III. If the fan does not work after starting, do not touch the impeller, rotor, or other parts, professional technical personnel are required to inspect the fan to prevent sudden start of the fan from causing hand or other personal injury

IV. Because of the soft start characteristics of the fan, to prevent personal injury, do not touch the impeller or other parts of the fan during powered on or running at low speeds

V. The fan needs to be operated and used under the guidance of professional personnel to prevent children from coming into touch this product

VI. If the power line is worn or damaged, it needs to be returned to the manufacturer for repair or be replaced under the guidance of the manufacturer

VII. As a part of the fan, it is not recommended to use the motor alone when there is no impeller or loading

Advantages

1. Ultra-Quiet Operation at Low Voltage: The FB3G250-24PL-90 achieves only 69 dB(A) at full speed — below normal conversation level — while delivering 1124.5 m³/h at 420 Pa. Operating on just 24VDC at 72W, it enables near-silent ventilation in noise-critical environments where AC fans would require bulky acoustic enclosures.

2. Exceptional Energy Efficiency: 75-80% aerodynamic efficiency through precision backward curved impeller design, consuming only 72W for 1124.5 m³/h — a 30-40% energy saving versus equivalent AC centrifugal fans, translating to lower battery capacity requirements and extended runtime in off-grid systems.

3. Wide Application Range: Ideal for medical equipment cooling, laboratory fume extraction, office HVAC, residential ERV/HRV systems, battery storage enclosure ventilation, and mobile shelter climate control. Available for OEM/ODM customization with your branding and connector specifications.

4. Sustainable Development: EC brushless motor technology reduces energy consumption by over 30% versus AC alternatives. IP44-rated die-cast aluminum housing and 50,000-hour L10 lifespan at 40°C minimize replacement frequency and total lifecycle cost.

5. Easy Installation and Maintenance: Standard 250mm mounting flange with ball bearings for any orientation. 0-10VDC/PWM control input and FG tach output enable plug-and-play automation integration. Maintenance-free BLDC motor requires no brush inspection or replacement.

FAQ

Q1: What kind of payments do you support?

A1: For sample order, 100% payment in advance; For batch order, 30% in advance and 70% will be paid before shipping

Q2: Will you provide samples?

A2: Sample is available and can be delivered within 7 days for standard models

Q3: How can I choose a more suitable model?

A3: We need the information like fan type, quantity, size, material, voltage, air flow and static pressure.

Q4: How can I place the order?

A4: Usually quote you within 24 hours after we get your inquiry. First sign the PI, pay deposit, then we will arrange the production. After finished production need you pay balance. Finally we will ship the Goods.

Q5: About transportation

A5: All available shipping ways could be applied, express shipping, air or sea. Appointed shipping company or our own forwarders all could be used in shipment. Full-way tracking the cargos for you before the goods arrive.

Q6: How long is the warranty period?

A6: We currently offer 3-year quality guarantee for our own products, and in response to current product problems, our company provides line support, and some customers have been able to improve their products.