Control-power source of double power source auto switching gear

The utility model discloses a control power source of a double power source automatic switching device, which is composed of double-transformer control circuits, wherein a set of transformer circuit is connected with a normal power source and the other set of the transformer circuit is connected with an emergency power source. The two sets of transformer circuits are respectively provided with a power source output which is supplied to a single-chip computer of a control unit of the double power source automatic switching device for using and a power source output which is supplied to a controlling relay for using. The power source outputs which are supplied to the single-chip computer of the control unit of the double power source automatic switching device for using of the two sets of transformer circuits are connected together. The power source outputs which are respectively supplied to the controlling relay for using of the two sets of transformer circuits are connected together. The two sets of transformer circuits are also respectively provided with an independent power source output which is used for detecting the normal power source and the emergency power source. A uninterruptible power source USP can be saved by the double power source automatic switching device of the control power source, a double-contactor can be saved, and the utility model is more reliable than a control circuit which uses a contactor as the switchover and can be widely used for the double power source automatic switching device.