I have two dear friends of impact crusher brand robins Hewitt is the primary crusher is 200HP and secondary crusher is 400HP. If anyone has the operating manuals of these crushers please send me to my mail mpereyraoyarce@gmail.com. These crushers have bought them used and have problems with premature wear of impact pads and rotor bars although these are chrome molybdenum alloy. The plates have only lasted me 15 days ■