How real electric motors work - School of Physics - The University of ...

UNIVERSITY OF NEW SOUTH WALES - SYDNEY - AUSTRALIA
If we energise the Phase A coils, the rotor will turn so its teeth line up with the teeth of that phase.
Now, if we energise Phase B as well, the rotor will turn slightly because the teeth of the Phase B are
not aligned with those of Phase A. Now we de-energise Phase A, and the rotor will align fully with
the teeth of Phase B. Next we energise Phase A with the reverse polarity to before, de-energise Phase
B, energise Phase B with the reverse polarity, de-energise Phase A, re-energise Phase A with the
original polarity, and we’ve made one full step! If we were writing this down as series of dance steps
for a barn dance it would probably look something like: A+ A+B+ B+ A-B+ A- A-B- B- A+B- A+.
There are many other varieties of stepper motors. Some have no magnets on the rotor (so-called
switched reluctance stepper motors), and some have magnets but no iron.