An environmental containment system has a wall frame for mounting to a wall. Features in the speech and in the data in at least one further modality are identified. And the controller is configured to determine a position of the rotor based on the inductance of the motor, and control operation of the motor based on the position of the rotor. The third gear wheel also engages with the first gear wheel by way of helical gearing and being axially shiftable with respect to the second gear wheel.