| 摘要 |
PURPOSE:To surely cut off electricity fed to a lamp in case of abnormality occurrence by using a normally open contact as a switching contact. CONSTITUTION:The lamp turning-on device is equipped with the lamp 4 which is connected to a power source 1 through the normally open contact 2, a switching device 6 which makes and breaks the normally open contact 2, and an applied voltage detecting means 5 which detects the applied voltage of the lamp 4. Further, the device is equipped with a control means 12 which breaks the normally open contact 2 when the continuance of the feeding of the lamp applied voltage detected by the applied voltage detecting means 5 exceeds a set time continuously while the lamp 4 is fed with electricity by making the normally open contact 2 by the switching device 6 to illuminate. Namely, the switching contact is the normally open contact 2 and excited in the normally open state, so even if an exciting coil is turned off owing to trouble of the switching device 6, the contact 2 is excited in the open state at all times. Therefore, the electricity feeding to the lamp 4 is cut off at the time of the trouble of the switching device 6, etc., so what is called fail-safe effect is obtained. |
