  Using numerical simulations at moderate magnetic Reynolds numbers up to 220
it is shown that in the kinematic regime, isotropic helical turbulence leads to
an alpha effect and a turbulent diffusivity whose values are independent of the
magnetic Reynolds number, $\Rm$, provided $\Rm$ exceeds unity. These turbulent
coefficients are also consistent with expectations from the first order
smoothing approximation. For small values of $\Rm$, alpha and turbulent
diffusivity are proportional to $\Rm$. Over finite time intervals meaningful
values of alpha and turbulent diffusivity can be obtained even when there is
small-scale dynamo action that produces strong magnetic fluctuations. This
suggests that small-scale dynamo-generated fields do not make a correlated
contribution to the mean electromotive force.
