LLI 750V – 3000V DC Live Line Indicators

The High Voltage DC Live Line Indicator Kit (LLI) is a battery operated electronic unit that has been specifi-cally designed to test DC systems, with relevance to Mass Transit Railway (Metro) & Tram based models. Although usually applied to overhead catenaries they can also be used on “third rail” installations. Proving that the system is de-energised, and can thus be safe-ly earthed, is important to both maintenance staff and system security.

The DC LLI gives both visual (high intensity flashing red LED’s) and audible (70dB) alarm should a conduc-tor under test indicate as live. Three versions are avail-able to cover the most common system voltages of 750V, 1500V and 3000V DC. Each version has a threshold setting of approximately 33% of system volt-age, above which the line is deemed to be energised.

The unit is first armed with the test button which will cause the alarms to activate and upon releasing the button the red LED’s will be replaced by green ones and the audible alarm will stop. The green condition will remain active for about 5 minutes during which time the unit can be applied to the line under test and if the threshold is exceeded the warning alarms will again be activated. Pressing the test button also per-forms a battery check. A universal “star wheel” adaptor is also available to connect to other operating poles and alternative clamps are available to suit various earthing systems, e.g., buried rail.

Each complete LLI kit comprises:
• DC Live Line Indicator with earth lead & clamp
• Bowthorpe Rod adaptor incorporated into indicator case moulding
• Universal Star wheel Adaptor
• Hook, Y and straight electrode
• Polymer cleaning kit
• Instruction manual
• Carry satchel