Smoke extraction electric motors are purpose-built asynchronous motors that drive the jet fans and axial fans responsible for clearing smoke and hot gases away from escape routes during a fire. Unlike ordinary ventilation motors, their defining feature is the ability to keep running at very high temperatures for a defined period.

Temperature Endurance Classes

These motors are rated in classes such as F300 and F400; an F400 motor, for example, continues to operate at 400 degrees Celsius for two hours. This endurance comes from Class F insulation combined with special winding varnishes, high-temperature bearing grease and the thermal stability of the cast iron housing. A standard IP55 motor would fail quickly under these conditions, whereas a smoke extraction motor stays operational throughout the evacuation period.

Single-Speed and Two-Speed Solutions

In car parks and enclosed areas, two-speed (Dahlander) wound motors are common: the low speed handles everyday ventilation while the high speed delivers full extraction during a fire. On a 50 Hz supply a 4-pole winding gives 1500 rpm and a 2-pole winding 3000 rpm, with both stages combined in one motor frame. This reduces energy use and serves two functions from a single unit.

Mounting and Protection Details

In jet fan applications the motors are usually foot-mounted (B3) or flange-mounted (B5) integrated into the fan hub. The terminal box and cable glands are selected for high temperature, and thermal protection elements are embedded directly in the windings. IP55 protection shields the motor from dust and moisture in the car park environment while keeping it functional in a fire scenario.

The Right Smoke Extraction Motor for Your Project

The correct class must be chosen according to the building's fire scenario and the endurance period required by the relevant regulation. DRG Motor, a supplier based in Izmir, supplies smoke extraction motors in the appropriate pole count, speed and temperature class for car park and tunnel ventilation projects; contact us for a quotation based on your project details.