The ornamental design for a portablegeneratorlockdownplate, as shown and described.
FIG. 1 is a perspective view of a portable generator lockdown plate in accordance with the present invention.
FIG. 2 is a bottom view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a side elevational view thereof;
FIG. 5 is a front elevational view thereof;
FIG. 6 is a rear elevational view thereof; and,
FIG. 7 is an exploded perspective view thereof.
The broken lines in the drawing views are included for the purpose of illustrating portions of the portable generator lockdown plate that form no part of the claimed design.