  We study the transfer of energy between different scales for forced
three-dimensional MHD turbulent flows in the kinematic dynamo regime. Two
different forces are examined: a non-helical Taylor Green flow with magnetic
Prandtl number P_M=0.4, and a helical ABC flow with P_M=1. This analysis allows
us to examine which scales of the velocity flow are responsible for dynamo
action, and identify which scales of the magnetic field receive energy directly
from the velocity field and which scales receive magnetic energy through the
cascade of the magnetic field from large to small scales. Our results show that
the turbulent velocity fluctuations are responsible for the magnetic field
amplification in the small scales (small scale dynamo) while the large scale
field is amplified mostly due to the large scale flow. A direct cascade of the
magnetic field energy from large to small scales is also present and is a
complementary mechanism for the increase of the magnetic field in the small
scales. Input of energy from the velocity field in the small magnetic scales
dominates over the energy that is cascaded down from the large scales until the
large-scale peak of the magnetic energy spectrum is reached. At even smaller
scales, most of the magnetic energy input is from the cascading process.
