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Since live cables in operation are not allowed to damage any grounding wires or other connecting wires, nor is it allowed to directly apply the output signal of the identifier transmitter to the cable phase wires with high voltage. Live cable identification needs to solve two difficulties: first, how to couple the cable identification signal onto the cable; second, the coupled signal is generally small, while operating cables may have 50Hz unbalanced current, induced 50Hz interference current, and distributed capacitance current, etc., which constitute 50Hz power frequency electromagnetic interference. The high-sensitivity receiving clamp thus faces the problem of how to resist 50Hz power frequency interference.

The live cable identifier we developed uses microcontroller encoding and decoding technology in both the transmitter and receiver, as well as PSK technology widely used in the communication field. The transmitting clamp emits a phase-encoded signal with an average value of 0. The microcontroller in the receiving clamp filters the received signal through hardware and software, then performs phase identification. When the receiving clamp is clamped onto the cable according to the current direction, the ammeter of the identified cable deflects to the right, accompanied by audible and visual indication. For other cables, the current direction is opposite to that of the identified cable, so the ammeter pointer deflects to the left, with no audible or visual indication. This demonstrates the uniqueness of the target cable to be identified, making it easy to distinguish the identified cable from multiple cables. Moreover, since the signal current intensity on the identified cable is the same along the entire line, the electromagnetic signal intensity received by the receiving clamp along the cable is consistent. In principle, the identification of the cable is not limited by the length of the cable to be identified.

1. Maximum pulse peak output current: 20A

3. Power supply: AC220V (-10%~+10%), power not greater than 100W

4. Weight: not greater than 12kg

Receiver sensitivity: grounding loop resistance less than 50 ohms

1. Connect the transmitting source: Insert the red and black plug connectors of the transmitting clamp A into the corresponding red and black binding posts on the transmitting source, and clamp the transmitting clamp A onto the cable to be identified. The arrow on the transmitting clamp A points toward the cable terminal. Both ends of the identified cable should be reliably grounded. For non-operating cables, the core wires at both ends can also be grounded.

2. Turn on the power switches of the transmitting source and receiver to check the direction: On the identified cable at a distance of more than two meters from the transmitting clamp, clamp the receiving clamp B onto the cable, with the arrow on the clamp always pointing toward the cable terminal. Then check the current direction and test connection direction. At this time, the ammeter pointer of the receiver must deflect to the right, accompanied by audible and visual indication, as shown in the figure. If the arrow of the receiving clamp B points toward the transmitting source end, there will be no audible or visual indication, and the ammeter pointer will deflect to the left. Remember the deflection direction of the receiving clamp's ammeter.

3. Identification: At the identification point, use the receiving clamp B to identify each cable. During identification, always keep the arrow on the receiving clamp pointing toward the cable terminal direction, and test each cable one by one. On the identified cable, the ammeter pointer of the receiver must deflect to the right, accompanied by audible and visual alarm indication. On other cables, the ammeter pointer of the receiver must deflect to the left, with no audible or visual alarm indication. The cable where the receiver ammeter pointer deflects to the right with audible and visual alarm indication is the cable to be found and identified. This test result is unique. That is, no matter how many cables are in the cable trench, when using the receiving clamp B to identify each cable, only one cable (the cable to be found and identified) will have the receiver ammeter pointer deflecting to the right with audible and visual alarm indication.