Contactors in RPC

Ok i got a few quistions about contactors. Im biulding my 15hp RPC to push button start. And in doing so I want to size contactors for a 20hp so i can up grade in future i know i need at least 90 amp contactor for the main and about 80a 3pole for the start caps. My quistion is 24v 120v 240v and all inbetween is there one that works better for an RPC. I know 24v is low voltage but then need transformer. is a 240v better more egual draw on the incoming power vs 120v. I think im buying new so equally easy to find. witch leads to next quistion i found new Packard brand cotactors on Ebay for 80$ seems good price vs SD or Simions ther 150$ plus. i found when you get this big in contactors they get spendy. I was looking at a 15hp wny kit on ebay for 115$ caps contactors relay witch is cheaper than dirt and tryed asking the amp rating on the contactors and got no answer wasnt trying to steel secrets of his product but confused on how he can sale them so cheaply is he useing under sized components wher ill have close to 300$ in mine when done trying to be cheap

First thing is it would help understand what it is you are trying to do if you would use rules of grammar, spelling and punctuation.

Reading between the lines, are you asking why the supplier's contactors are so cheap compared to NEMA starters? If so, there are many different kinds and ratings for contactors. NEMA contactors are far more rugged, with longer mechanical and electrical lives than DP (definite purpose) contactors. Also, there are much better profit margins in NEMA devices then DP.

Is this what you are asking?

Tom