carrretero:
Modified wave inverter caused it to burn. No other visible damage to the circuitry.No arduino connection, I was just looking for a place where I might get an answer.
So you powered the pump with a supply it was not designed for.
You could guess what the value of the resistor was and if you had the knowledge and experience to measure and work out what the resistor value should be then go ahead, but I guess it depends on your aversion to fires.
Sorry if this does not belong here.
Contact the pump manufacturer, they can advice you on what is the (safe) value of resistor to use.