I've got a list of Polish Cavalry Ranks. I'm not too sure of their validity, but they make sense. I'll seperate them by their Polish name, the abbreviation, and the English Counterpart. I also incleded some comments, cause the ranks are a bit odd.
szeregowiec szer. Private (General term for ranker)
dragon drag. Dragoon (Private for Dragoon regiments)
ulan ul. Lancer (Private for Lancer regiments)
starszy dragon st.drag. Older Dragoon (Lance Corporal for Dragoon regiments)
starszy ulan st. ul. Older Lancer (Lance Corporal for Lancer regiments)
kapral kapr. Corporal
plutonowy plut. Lance Sergeant
wachmistrz wachm. Sergeant of Horse
podporucznik ppor. Second-Lieutenant
porucznik por. Lieutenant
rotmistrz rtm. Captain of Horse
major mjr. Major
podpulkownik pplk. Lieutenant-Colonel
pulkownik plk. Colonel
I tried my best with these. It's all I could find on the subject.