What the ratings mean for a 24 V rail
The 1.5KE30-E3/54: Its 24.3 V reverse standoff voltage sits just above a nominal 24 VDC rail, so it stays out of conduction during normal operation and only clamps when a transient pushes the line above 27 V breakdown. The 43.5 V clamping voltage at 34.5 A peak pulse current defines the maximum voltage the downstream circuitry sees during a surge event — a figure to check against the absolute-max ratings of the powered devices on that rail.
Obsolete — sourcing through independent channels
Vishay lists this part as Obsolete.
Temperature range and package fit
Housed in a DO-201AA (DO-27) axial leaded package, the 1.5KE30-/54 mounts through hole and suits point-to-point wiring or PCB layouts where the axial body is soldered into plated holes.