4287670 Original Excavator Fusible-link for Hitachi EX200-5

Part number 4287670 is a pure melting chain produced by Hitachi Japan, used for the support chain (chain link) system of track type equipment. On super large excavators such as EX200-5, this melting chain is usually installed in the "walking motor brake release" or similar safety protection circuit as a temperature sensing protection element. Its universal model mainly covers EX200-5 models on the same platform, and is also applicable to EX series ultra large equipment such as EX1200-5 and EX1900-5 with the same support chain and walking brake system design. As a disposable temperature protection device designated by the original factory, its melting temperature is precisely matched with electrical parameters and protection circuit

This product is a disposable temperature fuse (melting chain), with a black high-temperature resistant plastic shell as the main body and a silver white metal piece protruding from one end as the terminal block. Its core is the low melting point alloy inside. When the ambient temperature reaches its rated melting temperature (usually set at specific values such as 85 ℃, 92 ℃, 105 ℃ according to Hitachi standards), the alloy melts and permanently cuts off the circuit under the action of the spring. Unlike ordinary current fuses, it is only temperature sensitive and not current sensitive. Its working voltage is usually at the vehicle level, and the rated current is relatively small. The complete original factory information (part number, QR code, certification mark) on the packaging ensures its traceability and reliability. The core function is to automatically fuse when the temperature rises abnormally in a specific area (such as near the walking motor brake), cut off the relevant control circuit, trigger protective actions or alarms, and prevent overheating faults from expanding.

Fault diagnosis: When specific functions of the equipment fail, such as the inability to release the walking brake, and there is no direct alarm from the instrument, after troubleshooting the power supply and relay, the melting chain should be checked. Testing method: Use a multimeter to measure the on/off state of both ends, which should be in a conductive state. If it is a circuit breaker, it has already blown. Replacement timing: This component is disposable and must be replaced once it melts. Melting usually indicates that the relevant parts have been overheated. After replacement, it is necessary to check and eliminate the root cause of overheating (such as brake drag, poor lubrication, circuit short circuit, etc.).