It appears to be an X13 motor using the low, low-medium, and medium taps. When the thermostat calls for first-stage emergency heat, the low and low-medium taps are effectively shorted through the thermostat. (That is, they are both energized from the same 24vac source.)
Just to resolve this thread. I spoke to a Genteq technical support rep and he stated that the X13 motors can have any or all of the low voltage taps energized at once and the motor will simply run at the speed of the highest tap energized at the time.