so we had our envelope machine modified and the tech that did it cant get it right . this machine has to move 1 to 1 every time the motor rotates . so after he tore it down he got new drives and installed new dynamic brakes and now he cant get the motors to start at the same time or stop at the same time ... i'm not much of of a tech . the motors are 480v ac 20hp & 15hp and now he is talking about installing encoders ..... if you need more info just let me know and i will do my best to get you the info