Burn-out sensing device for series lighting circuit

Abstract

Abstract PURPOSE:To enable sensing burn-out of filament and its location even if only one of the lighting loads has encountered burn-out, by sensing the current value or impedance flowing in a sensing cable using such a measuring instrument as ammeter, impedance gauge, etc. CONSTITUTION:In case the n'th lighting load Ln has encountered burn-out, a current sensing relay Ryn senses it and shuts the corresponding relay contact Sn. This forms a closed following a DC power supply 4, ammeter 5, cable resistance R1, resistance element Z1, cable resistance R2, resistance element Z2 cable resistance Rn, resistance element Zn, relay contact Sn, and the ground, and also current In flows through the ammeter 5. The amperage In at this time is In=100/SIGMA(Rn+Zn). That is, current flows in the event of even a single burn- out, which can be sensed by measuring the current value flowing through the ammeter 5, and the magnitude of the amperage serves identification of the place of burn-out. In stead of ammeter, sensing can also be made with an impedance gauge.

Inventors

• 👤 Atsushi Ito
• 👤 Kazuaki Shibata

Bibliographic Details