| 摘要 |
PURPOSE:To easily check whether the connection to a power supply and the earth connection are correct or not by a method wherein a normally open inspection switch is connected between the line side terminal of power terminals and the earth terminal of a main body. CONSTITUTION:A series circuit consisting of a normally open inspection switch 12, a neon lamp 13, and a current limiting resistor 14 is connected between the line side terminal L of power terminals and an earth terminal E. If the connection to a power supply is connected with reversed polarity of power terminal L and N, both the ends of the neon lamp 13 is fall to the earth and consequently the neon lamp 13 does not light. Furthermore, if the earth terminal E is incorrectly grounded, the neon lamp 13 also does not light, even when the power supply is correctly connected, because one terminal of the neon lamp 13 turns to be open. |
