  We present sensitivity limits on the coefficients of a dimension-6 effective
Lagrangian that parametrizes the possible effects of new physics beyond the
Standard Model. Our results are based on the study of the process $e^+ e^- \to
W^+ W^- \gamma$ at LEP2 and NLC energies. In our calculations, we include all
the new anomalous interactions, involving vector and Higgs bosons, and take
into account the Standard Model irreducible background. We analyse the impact
of these new interactions on the total cross section, including the effects of
the initial electron and final W polarizations. We then focus on the operators
that will not be constrained by the $e^+ e^- \to W^+ W^-$ process, obtaining
limits based on the photon energy distribution.
