2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/7575We have analyzed archival HST/WFPC2 time-series data of the central parts of globular clusters M13, M30 and NGC 6712 in search of variable objects. Among a total of 21 identified variables there are 15 new discoveries. The sample includes nine RR Lyr stars, two SX Phe stars and seven W UMa-type contact binaries. One object is preliminarily classified as a detached eclipsing binary and another as an ellipsoidal variable.17 pages, 9 figures, accepted for publication in Acta AstronomicaAstrophysicstext