Helios Fans HRFD 355÷4÷4

The Helios HRFD 355÷4÷4 is a high-efficiency cased axial fan engineered for industrial and commercial ventilation systems requiring dual-speed operation. This model features a direct drive design with star/​delta switching, allowing flexible control of airflow based on system demands.

Constructed with a cylindrical duct housing made from galvanised sheet steel, the unit includes flanges on both ends for seamless installation into duct systems. The housing and flange configurations adhere to DIN 24155 standards, and a conveniently placed external terminal box ensures easy electrical access.

The fan’s impeller is precision-engineered with aerodynamically profiled blades made from impact-resistant polymers. Dynamically balanced, the impeller delivers smooth performance and consistent airflow at temperatures ranging from ‑30 °C to +60 °C.

Power is provided by a totally enclosed 3‑phase squirrel cage motor featuring star/​delta switching for two-speed functionality. Designed for durability and quiet operation, the motor is maintenance-free with sealed-for-life ball bearings. The HRFD 355÷4÷4 is ideal for industrial ventilation applications requiring energy-efficient airflow with variable speed capabilities.