We use a simple analytic model for the evolution
of currents in superconducting strings to estimate
the strength of the `seed' magnetic fields generated
by these strings. This model is an extension of
the string network evolution model of the present authors
dependingon a parameter $f$ which characterizes the importance
of equilibration processes in the evolution of the currents.
For GUT-scale strings or slightly lower energy, we find that a
viable seed magnetic field for the galactic dynamo can be
generated if the equilibration is weak. On the other hand,
electroweak-scale strings create magnetic fields
that are smaller than required.