The Series 21 brushless DC axial fans feature a plastic impeller (UL 94V-0) with seven blades and a die‑cast aluminum frame. They are designed for axial airflow with a compact size of 72 × 51 mm and weigh about 960 g.
Key performance figures include a rated voltage range of 32 V to 80 V, maximum speeds up to 5,500 RPM, airflow up to 408 CFM, and noise levels around 68 dBA. Part numbers such as DB17251‑48U identify specific variants with different speed and airflow ratings.
| Impeller material | Plastic (UL 94V-0) |
|---|---|
| Frame material | Diecast Aluminum |
| Weight | 960 g (33.86 oz) |
| Rated voltage range | 32 V to 80 V |
The impeller is made of plastic meeting UL 94V-0 standards.
The fans operate within a voltage range of 32 V to 80 V.
Noise is measured in an anechoic chamber in free air, one meter from the intake side.