Customer Requirement
An OEM producing air purification systems and agricultural ventilation equipment needed a variable-speed forward-curved centrifugal blower. As filter resistance would increase during operation, the fan needed adjustable speed to maintain the required airflow. Installation space was limited, with the blower required to fit within 243 × 282 × 285 mm (W × H × D).
An OEM customer manufactures air purification and agricultural ventilation equipment. For this project, they were looking for a variable-speed forward-curved centrifugal blower. One concern was filter loading. As resistance increases over time, airflow can drop, so the blower needed enough speed adjustment to compensate. Space was another limitation. The available installation area was 243 × 282 × 285 mm (W × H × D).
Electrical constraints were equally specific. The centrifugal blower needed to run on a standard 220 VAC, 50/60 Hz supply. Because the intended deployment environments varied considerably, the unit should have a wide rated operating temperature range, from -25°C to 50°C.
Aerodynamic performance of this centrifugal blower had to be verified according to ISO5801-1997 testing protocols using standardized airways. The customer also required the fan to meet EN60335-1 safety standards for household and similar electrical appliances. Because a fixed-speed AC fan cannot automatically ramp up its speed as particulate matter clogs a HEPA filter, the procurement team expressly mandated an EC (electronically commutated) motor capable of accepting external control signals. IP54 protection was specified to guard the internal electronics against dust and splashing water inherent in agricultural grow tent applications and industrial air filtration.
Engineering Solution
A backward-curved plug fan was evaluated during the initial design stage but was not suitable for the required airflow path. The customer’s air handling unit needed directional horizontal discharge through the primary filter bank, so LONGWELL selected a forward-curved centrifugal fan with a volute housing. A conventional AC motor with an external inverter was also avoided because the additional components would have increased installation space and control-panel heat.
LONGWELL selected the LWDD7-5-C-EC-002, which uses a brushless EC external rotor motor and direct-drive design. The complete blower fits within the required installation space without the need for an additional transmission mechanism. The volute housing and forward-curved impeller are made from galvanized steel. For long-term operation, the fan uses maintenance-free ball bearings and a dynamically balanced impeller to G6.3 grade. The specified bearing life is 30,000 hours L10 at 40°C.
The integrated SmartEC™ motor supports 0–10V, PWM, and RS485 speed control, allowing the fan to adjust to changing airflow resistance as the filters load. At a representative operating point, the fan delivers 1603.33 m³/h at 216.16 Pa, drawing 253 W at 1554 RPM. Class F insulation supports operation at ambient temperatures up to 50°C.
Technical Specifications
| Parameter | Value |
|---|---|
| Nominal Voltage | 220 VAC |
| Frequency | 50/60 Hz |
| Speed | 1356 ± 10% rpm |
| Current (Max) | 1.93 A |
| Power Input (Max) | 250 W |
| Air flow (Max) | 1980 m³/h (1165 CFM) |
| Static pressure (Max) | 317 Pa |
| Max. Ambient Temp | 50 °C |
| Min. Ambient Temp | -25 °C |
| Insulation Class | Class F |
| Protection Type | IP54 |
| Work System | S1 (Continuous) |
| Life Expectancy | 30,000 Hours (L10) at 40°C |
| Balancing Precision | G6.3 (JB/T9101) |
Technical Documentation
LONGWELL-DD7-5-EC-Spec-Sheet.pdf
This comprehensive engineering specification includes P-Q performance curves, dimensional drawings, and safety guidelines required by system integrators during the OEM design phase.
Why LONGWELL Centrifugal Blower for Air Filtration System?
- LONGWELL centrifugal blower can generate high airflow volume with high static pressure. Even when the filter load gradually increases, the DD-series model equipped with an EC motor can still maintain a stable centrifugal force continuously.
- The centrifugal blowers are suitable for industrial and commercial air filtration systems. Their dynamically balanced impellers and durable components support stable operation under long-term and high-load conditions.
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SmartEC™ motor supports variable-speed operation, allowing airflow to be adjusted according to actual filtration demand. This helps reduce unnecessary energy consumption while maintaining the required system performance.
- The forward-curved centrifugal blower is compact, which can be integrated into different filtration equipment layouts. The available installation options make adaptation easier for OEM system designs.
Explore our full Centrifugal Fans range.
Frequently Asked Questions
Q: Is the LWDD7-5-C-EC-002 suitable for operation below 0°C?
A: Yes. The fan can operate at ambient temperatures down to −25°C. Its galvanized steel impeller and volute housing, together with the EC motor electronics, are designed for low-temperature conditions.
Q: Can a BMS adjust the blower speed automatically?
A: Yes. This centrifugal blower accepts 0–10V or PWM control signals, so a building management system or central controller can adjust the motor speed according to actual ventilation demand rather than keeping it at a fixed RPM.
Q: How does the fan communicate its actual operating speed back to the controller?
A: The motor wiring harness includes a fine blue wire designated for FG output. This line transmits real-time tachometer pulses back to the control board, allowing precise monitoring of the speed.
Technical Documentation & Resources
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Project Item: 7070944891-DD7-5
Project Date: 2026-08-11 02:18:07
