工業(yè)照明電源控制

　　在選擇光源時，工業(yè)用戶面臨著許多壓力。法規(guī)和經濟壓力迫使他們投資于節(jié)能照明，包括發(fā)光二極管（LED），可以提供長壽命，因此可以讓公司降低維修成本。

　　然而，照明技術的改變并不是實現經濟目標的必要條件。照明燈具的智能電源為工業(yè)用戶提供了多種選擇，使他們更容易選擇適合應用的光源。

　　高強度放電燈（HID）金屬鹵化物燈已成為工業(yè)用戶中最受歡迎的選擇之一，尤其是在大面積需要有效覆蓋的情況下，如裝載艙和高天花板倉庫。總的概念與熒光燈相似，因為當離子通過兩個電極間的電流時，光是由離子產生的。然而，與熒光光源不同，熒光粉不需要將光子從紫外光轉換成可見光光譜。離子在一個很窄的頻率范圍內釋放可見光光子，使燈具有一種特殊的顏色。

　　Although simple in concept， HID lamps call for careful power control to maximize energy efficiency. They require a high initial voltage for ignition – around 3 to 4 kV if the lamp is cold， and as much as 20 kV if the lamp is still warm. As the lamp warms up， the current needs to be limited until it is fully running.

　　Before ignition， the arc gap inside the lamp presents an open circuit. But， once it ignites and starts to conduct， the voltage across the lamp drops sharply to around 20 V. Current， if not limited， can build up to a very high and damaging level. However， as the lamp warms up， the voltage – and output power – increases until it settles to a nominal value of around 100 V. After this point the current supplied needs to be maintained at a constant level that is well matched across the lamps in an array to avoid color and brightness variation.