The D3/LLI Live Line Indicator is a resistive type voltage detector designed for use on overhead a.c. rail electrification systems operating at 25kV nominal voltage. The ‘LLI’ threshold is specified as 12kV ± 5%, however it should be noted that induced voltages could reach 10kV.

The unit is designed to be mounted on approved fiberglass earth poles with the pole immediately below the indicator being the primary insulator (ref
91-2410). The signal emitted by the D3/LLI is both audible and visible. Power is provided by a rechargeable battery, housed within the main unit. The battery can be charged in situ using the charger supplied.

The unit comprises a main unit and a contact probe. The contact probe is manufactured from lightweight fiberglass tubing and houses the calibrated resistor stack. The pole section is foam-filled to increase its voltage withstand. The probe is connected to the overhead line by a replaceable aluminum hook. The top of the pole is coated in a
special high reflective paint to ease visibility when applying the indicator in poor lighting conditions.

The limit of contact with the overhead line is clearly defined by a red limit collar fixed to the pole. The contact probe screws into the main unit with a special screw connector to minimize flash-over.

Product Benefits

• Approval Reference PA05/798
• Audible and visual warning
• Self-test function
• Fully interchangeable
• Insulation tested
• Compatible with primary insulator poles

The D3/LLI live line indicator is a resistive type voltage detector designed for use on a.c. rail electrication systems operating at 25kV nominal voltage. The ‘LLI’ threshold is specied as 12kV ± 5%, however it should be noted that induced voltages could reach 10kV. The unit is designed to be mounted on approved breglass earth poles, the pole immediately above the handle pole being the primary insulator (ref 91-2470). The signal emitted by the D3/LLI is both audible and visible. Power is provided by a rechargeable battery. It is important that the indicator is tested for correct operation before and after use in case any deterioration has occurred. Press the black ON/OFF button and the green light will illuminate and will remain illuminated for a period of 5 minutes. Pressing the ON/OFF button again will restart the 5 minute cycle. It is not possible to switch o the indicator before the cycle has elapsed. This function prevents accidentally discharging the battery. There are two TEST circuits both of which should be activated before and after using the indicator as they test dierent functions. For both tests, the hook at the end of the contact electrode should be placed in contact with the rail ‘earthing’ magnet. Thereafter, follow the procedures below:-

A: Press and hold the lower red TEST button – this checks correct operation of the circuitry, sounder, LEDs and circuit resistance. The green light should ‘change’to the red light and the audible signal sound continuously. When the TEST button is released the indicator should return to the green stand-by state.

B: Press and hold the upper red TEST button – this checks the resistance and continuity of the contact electrode. After a short delay the green light should ‘change’to the red light and the audible signal sound continuously. When the TEST button is released the indicator should return to the green standby state. If neither of the above tests work, then the indicator should be removed from service. Initially try recharging the battery and then repeat the tests. If again the tests do not work, remove the indicator from service and contact us.

The ‘LLI’ should be applied only in accordance with supervisory instructions by authorised persons and all normal safety precautions taken.

1. Apply the magnet to a clean section of bonded rail
2. Clean and assemble the earth poles, primary insulator and LLI
3. Switch on the indicator and carry out tests A&B detailed as above
4. Ensure that the point of test has no surrounding conductors that could compromise the limit mark (disc) on the contact probe
5. Place the hook over the conductor and verify the absence of voltage. Voltage is present if the light changes to red and the audible alter sounds
6. Remove the indicator and repeat tests A&B above to conrm result
7. Remove the LLI from the earth poles before removing the earth magnet

Periodically it will be necessary to recharge the battery at the base of the indicator. Working practices specify that the indicator should be recertied for use by an approved test station such as ourselves, ideally every three months.

If any doubt exists regarding the operation of the LLI, DO NOT USE the indicator.
Any evidence that the indicator had been tampered with will invalidate the warranty.

Periodically, it will be necessary to change the battery in the detector. The battery is housed in the main body and access is gained by loosening the retaining screw and removing the switch/battery housing. A special tool is available for this operation, alternatively, we are able to t these and recertify the equipment when required.

The detector and associated parts should be stored in a dry atmosphere away from airborne contaminants, in its carrying/storage bag.

Components should be cleaned with a suitable high voltage equipment cleaner, solvent and salt based cleaners must be avoided. All damaged components should be replaced or returned for repair. We oer a complete calibration and insulation test service, all repairs being undertaken on a quotation basis.