I just bought a 1/2 hp dc motor to replaced a smaller one who was working well except it overheated after a while. the motor is driven by a KB scr drive. When free running everything seem well, it vibrate on start but pick up its speed and is eventually humming. when the work load is attached, there is a strong vibration shaking the whole thing. no matter what speed the pot is ajusted, it ring loudly. i tried another drive, also SCR drive, from another manufacturer and it seem even worst. i took the motor to the repair shop they put it on a test and everything is ok, they say there must be a match between some motor and some scr drives. well how to do that? i would like better to understand what is going on anr fis the mismatch by adding perhaps a condenser or a choke or a combination or modifying the brushes or what....
can some one help me on this one?