What the 1500W rating means for your board
The 1.5KE22A-HF: This is the headline figure that defines the surge it can absorb — a 49.02A peak pulse current gets clamped to 30.6V max before the device self-limits. The reverse standoff voltage is 18.8V, meaning the diode stays transparent on a nominal 12V or 15V rail and only starts conducting when the transient exceeds 20.9V breakdown (minimum). For a 24V bus, this part is too low — you would want the 1.5KE24A variant instead.
Package and mounting — through-hole axial
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE22A-HF is a through-hole device. The DO-201 footprint is standard for 1500W TVS diodes — the large body and thick leads handle the thermal pulse without lifting pads. No power line protection (it is a unidirectional Zener, not a bidirectional or steering array).