Alternator 714/40526 JCB JS, aftermarket

For the JCB JS crawler excavators: alternator 714/40526, an aftermarket part. The card also lists 02/802633.

On excavators the alternator feeds the 24 V electrical system and charges two batteries connected in series. With the engine running, the charging voltage in a 24 V system should be roughly 27-28.5 V: below that means undercharging, above it overcharging. The alternator's terminal type (L, W and B+) must match the machine's harness. Check the belt tensioner and pulley when changing the alternator, since a worn tensioner makes the belt slip and undercharge. Measure the charging voltage after fitting. On excavators the alternator usually shares its belt with the A/C compressor and fan, so the condition of the belt and tensioner directly affects charging. The vent holes at the back of the alternator must not be clogged with mud, otherwise it overheats and its diodes are damaged.

Specifications

Compatibility

According to the product card, this is the alternator for Isuzu-engined JCB JS excavators. Other parts are in Alternators.

Fitting

Never disconnect the battery with the engine running and the alternator connected, since a voltage surge can damage the alternator diodes and electronic units. Disconnect the battery and alternator before any welding.