slo-syn driver questions

[dertsap]

has anyone got these drivers ,they are slosyn 430-t i scored 3 of them for pretty cheap , and i was wondering if there are any issues or pointer in using these , i think everything looks fairly straight forward with connecting them , these are going on my son's machine , one concern ive got is one of the motors is a 4 amp motor and the driver is 3.5 max , i plan to change the motor down the road , will i blow the driver connecting to a 4 amp motor or will the motor just be running under powered , i am assuming the later but worried about doing it all the same

[dertsap]

oops
meant to put this under stepper motors and drivers not servo