The formula i've found is:
5 x PI / (width x innerradius) x PI = windings per Volt
so in my case:
Width stator 1,575"
Inner radius stator 1"
Motor Voltage 115 V
15,7 / (1,575" x 1") x 3,14 = windings per Volt
15,7 / 4,95 = 3,17 windings per Volt
motor runs at 115V, that results in 365...