  A well-established, comprehensive 3-D numerical modulation model is applied
to simulate galactic protons, electrons and positrons from May 2011 to May
2015, including the solar magnetic polarity reversal of Solar Cycle 24. The
objective is to evaluate how these simulations compare with corresponding AMS
observations for 1.0-3.0 GV, and what underlying physics follows from this
comparison in order to improve our understanding on how the major physical
modulation processes change, especially particle drift, from a negative to a
positive magnetic polarity cycle. Apart from their local interstellar spectra,
electrons and positrons differ only in their drift patterns, but they differ
with protons in other ways such as their adiabatic energy changes at lower
rigidity. In order to complete the simulations for oppositely charged
particles, antiproton modeling results are obtained as well. Together, the
observations and the corresponding modeling indicate the difference in the
drift pattern before and after the recent polarity reversal and clarify to a
large extent the phenomenon of charge-sign dependence during this period. The
effect of global particle drift became negligible during this period of no
well-defined magnetic polarity. The resulting low values of all particles' MFPs
during the polarity reversal contrast their large values during solar minimum
activity, and as such expose the relative contributions and effects of the
different modulation processes from solar minimum to maximum activity. We find
that the drift scale starts recovering just after the polarity reversal, but
the MFPs keep decreasing or remain unchanged for some period after the polarity
reversal.
