1500 W peak pulse — the protection envelope
The 1.5KE62CAHE3/51: At that energy level it clamps a 17.6 A surge to 85 V maximum, protecting downstream electronics from transients like load dump or inductive kickback. The reverse standoff voltage is 53 V, meaning the diode stays high-impedance below that rail voltage and only starts conducting when the transient exceeds the 58.9 V minimum breakdown threshold. For a 48 V nominal bus or a 12 V system with high-voltage transients, this sets the trip point.