Fluorescent ballast within the -40 (continuous temperature) can work normally. However the fluorescent tube at -40 degrees can’t start. The fluorescent tube is evacuated, then full of a small amount of inert gas and mercury, the interior wall of the tube is coated with a layer of fluorescent powder. At both sides with preheating tungsten, tungsten coated with barium and strontium can due to the heat emission of electrons. If the temperature of tungsten oxide reached 950 degrees (power at both sides of the lamp tube, the luminous) coating surface oxide emission free electrons, starter disconnects instantaneous high voltage between your electrodes at both sides, ionizing inert gas arc is created between your tube (the lamp lit, we called it” startor”), the starting temperature increased after lamp, mercury heated and gasified, mercury vapor ionization conductive, the arc is maintained, produce ultraviolet light, ultraviolet light tube fluorescent material emits visible light. The ambient temperatures are too low in mercury lamp is difficultto be ionized, therefore it can’t start.