  The differential relation between the energy and electric charge of a dyon is
derived. The relation expresses the derivative of the energy with respect to
the electric charge in terms of the boundary value for the temporal component
of the dyon's electromagnetic potential. The use of the Hamiltonian formalism
and transition to the unitary gauge make it possible to show that this
derivative is proportional to the phase frequency of the electrically charged
massive gauge fields forming the dyon's core. It follows from the differential
relation that the energy and electric charge of the non-BPS dyon cannot be
arbitrarily large. Finally, the dyon's properties are investigated numerically
at different values of the model parameters.
