UV lamp keep shutting down
Your 1224 uses what are called metal halide lamps. “Metal halide” is a broad term used to describe a wide variety of gaseous discharge arc lamps in which the gas-filled arc tube operates at several times the normal atmospheric pressure. The various types of metal halide lamps are categorized and named by the type of additive contained within the arc tube. Examples are gallium, indium, cadmium and iron.On a practical basis metal halide lamps especially iron iodide lamps such as those used in the 1224 are fraught with operating issues. They are hard to start, must be run only at high power and are extremely easy to overcool. Metal halide lamps have a strict temperature profile and are not intended to be dimmed i.e. operated at reduced power. These lamps are designed, electrode chosen and bulbs shaped based on a certain power. Lamp output will not remain stable unless operated at high power level. Always start a lamp at high power.Iron iodide metal halide lamps are prone to overcooling. Lamps must have a minimum wall temperature in excess of 357oC, the boiling point of mercury. Below this temperature mercury and other additives will condense on the inner lamp surface turning the tubing dark silver to black. Once this plating has occurred, the effect is irreversible. It only takes a short time for an overcooled–glow mode–lamp to fail. A competent UV system will monitor lamp temperature and reduce cooling accordingly. An overcooled lamp willalways operate at reduced voltage resulting in lower UV output. Their light output will appear dim, certainly not as bright as a normal lamp and they will not come up to temperature.
As a metal halide lamp ages the operating voltage increases. The power supply (ballast) cannot support the increased voltage demand and the arc extinguishes. After cool down the lamp will light only to drop out again. Most likely this is happening in your machine. If you have ever seen a street light come on only to go out after several minutes, this is the same issue. You need to replace the UV lamps.
Gerard Fitzgerald
Engineer
TCS Technologies