The starter will turn the same direction either polarity
It doesn’t have permanent magnets in it like tiny dc motors that can spin the opposite way when you flip the polarity
The starter windings and the armature both reverse when you flip polarity
1x1= 1
-1x-1=1
No rotation change
This is how your old AC/DC vacuum cleaners work too
Each AC cycle flips polarity but it still turns the same way
And then of course direct current will also work
-s
