1. A device for driving a motor, the device comprising: a main housing configured to accommodate a circuit module therein, wherein a top of the main housing is partially opened to define an open portion; an input/output (IO) cover coupled to the main housing so as to occupy the open portion; and an auxiliary housing coupled to the main housing at an vertical side face of the main housing, wherein the auxiliary housing includes:a side face portion engaging with the vertical side face of the main housing;
a pair of brackets extending from both lateral ends of the side face portion respectively in a perpendicular manner to the side face portion;
bottom portions connected to bottom ends of the pair of brackets, wherein each of the bottom portions has at least one fourth coupling hole defined therein; and
an auxiliary cap structure coupled to the pair of brackets.