Hi there.
That's strange. I couldn't find any arms registered in the surname of WELTON, but there are several (13) registered in the surname of WELDON and four (in Ireland) in the surname of VELDON.
The arms that you 'led'* us to in the text of your post appear to be some that are produced by 'bucket shops' in an effort to gouge money out of unsuspecting heraldically naive members of the public. Those arms (well, the shield, anyway) depicts one of several registrations in the surname of WELDON to be found in Burke's General Armory (1884) with a blazon of Argent a Cinquefoil Gules on a Chief Gules a demi-Lion Argent.
However, that said, none of the WELDON registrations appear to carry the motto that is the subject of this thread who, if they have any motto at all, it is Bene Factum.
* Much better to attach a copy of that image to your post rather than lead the reader to a path that will cost them money to view your image.