FB3G250-48GL-91 DC Backward Centrifugal Fan, 48VDC, 250mm, 1716 m3/h

The FB3G250-48GL-91 is a 48VDC high-airflow DC backward centrifugal fan delivering an outstanding 1716 m³/h at 605 Pa — the highest airflow in the 250mm 48VDC series. Powered by the BLDC92 brushless motor at 2750 RPM drawing just 3.125A at 150W, it is purpose-built for telecom infrastructure operating on standard -48VDC power where maximum air movement is the primary requirement. The integrated FG tach output enables precision closed-loop speed control, compatible with 0-10VDC analog and PWM digital signals for seamless DCIM and BMS integration. Its wide 36-57 VDC input range ensures stable performance across telecom DC plant voltage variations. With IP44 ingress protection, Class B insulation, and 50,000-hour L10 service life, this fan delivers reliable high-volume ventilation for mission-critical DC infrastructure. Ideal for telecom shelter air exchange, data center heat rejection, DC microgrid equipment cooling, and industrial enclosure ventilation. CE and RoHS certified.

At the core of the FB3G250-48GL-91 is a BLDC92 external rotor brushless DC motor driving a backward curved centrifugal impeller with a 250mm diameter, optimized for maximum airflow at 2750 RPM. The aerodynamic design achieves 75-80% efficiency, converting 150W of 48VDC power into 1716 m³/h at 605 Pa — moving 11.4 m³/h per watt for exceptional air-moving efficiency from standard telecom -48VDC bus power. The motor's low 3.125A current draw across a 36-57 VDC range ensures compatibility with telecom DC plants, solar-battery hybrid systems, and DC microgrid installations. Its 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. Built-in protection includes soft-start, current limiting, locked-rotor protection, and reverse polarity protection. The fan features a die-cast aluminum IP44 housing, ball bearings for any orientation, and Class B insulation to 130°C. Rated for 50,000 hours L10 lifespan at 40°C, this fan is the optimal choice for 48VDC systems where maximizing airflow volume is the critical design parameter.

DC Backward Centrifugal Fan
Type	FB3G250-48GL-91
Model	BLDC92

Remarks:

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

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

Test condition:

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

II. Test voltage: 48VDC, 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.

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

1. Maximum 48VDC Airflow in 250mm Series: The FB3G250-48GL-91 achieves an outstanding 1716 m³/h at 605 Pa on standard telecom -48VDC power — the highest airflow rating among all 250mm 48VDC backward curved centrifugal fans. Ideal for high-volume air exchange in telecom shelters and DC-powered infrastructure.

2. High-Volume BLDC92 Efficiency: 75-80% aerodynamic efficiency at 2750 RPM, converting just 150W into 1716 m³/h at 605 Pa — moving 11.4 m³/h per watt with 30-40% energy savings versus AC alternatives.

3. Telecom & Industrial DC Applications: Purpose-built for telecom shelter air exchange, data center heat rejection, DC microgrid equipment cooling, battery storage ventilation, and industrial enclosure cooling. OEM/ODM available.

4. Reliable Continuous Operation: Die-cast aluminum IP44 housing, ball bearings, 50,000-hour L10 lifespan at 40°C, and 3-year warranty for always-on DC infrastructure cooling.

5. DCIM-Ready Integration: 0-10VDC/PWM plus FG tach for DCIM/BMS closed-loop control. Standard 250mm flange, any-orientation mounting, maintenance-free BLDC.

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.