A connector arrangement is provided for supplying electric power to a three-phase motor to produce motor operation in either a delta mode or a star mode, use being made of modular units that are removably mounted within a chamber contained in an outer frame that is secured to the motor housing. A power supply module arranged within the chamber includes a main receptacle containing a stack of terminal blocks having bus bars that transmit to the motor windings three-phase power that is supplied either by external power supply lines that extend into the chamber though openings contained in the side walls of the outer frame, or from an inverter arranged externally of the outer frame. Auxiliary receptacles are removably connected with the external surface of the main receptacle for monitoring the operating condition of the motor, or for controlling a motor operation, such as braking.