... Axial fan, Axial Flow Fan, Fan, Ventilator, Ventilation, Ventilating Fan, Ventilation, Ventilator Fan, Ventilation, Air Mover Application: Air ventilating and exhausting in ... stand-by fan at emergency switch-off of a running one;· automatic switch of stand-by low voltage input;· automatic ... the safety rules consists of two fans – a running one and a standby one – and of a set of tools for reversing ...