| 摘要 |
<p>PURPOSE:To monitor illumination regardless of an installation place of a ballast by detecting an electric current at a position closer to the electric power supply than the ballast and an electric current at a position closer to the electric discharge lamp side than the ballst. CONSTITUTION:An unlighted condition caused by abnormality of a lamp L is detected respectively by abnormality detecting means 31 and 32 according to voltages and electric currents on the primary side and the secondary side of a ballast 1, and either one of them is operated according to indication of an indicating means 36, and detected result output is displayed on a display means 34 through a display control means 33. Here, electric power is supplied to the control means 33 and the display means 34 in the daytime from a backup battery part 35. Thereby, abnormality can be displayed by selecting an abnormality detector according to a position of the ballast 1, so that exact monitoring becomes possible.</p> |
