The utility model discloses a many gears output transformer device of controllable switching, include: the automatically controlled contactor of transformer and array, the primary winding of transformer is including taking a percentage, or the secondary of transformer is including taking a percentage, or the primary winding of transformer and secondary are all including taking a percentage, the primary winding and the secondary interchangeable of transformer, the primary winding and the secondary of transformer all include the three -phase, this transformer device includes input and output, and the input passes through the one or more three -phase contact ware and connects primary winding, and the output passes through the one or more three -phase contact ware and connects secondary, outside electric pressure switching command is received to the automatically controlled contactor of array, carries out the contactor action that corresponds with electric pressure switching command to switch the combination of the input and the output of this transformer device. Many gears of the device output voltage carries out stepping up or stepping down of different brackets to mains voltage, satisfies multiplely by examination article needs.