An engine system comprising: an engine; a starter motor configured to start the engine; a transformer having a primary and a secondary, wherein a driving voltage (Vd) to the starter motor is an output of the secondary, and wherein the primary includes a first primary terminal, a second primary terminal and a branch terminal provided along a path of the primary; a power receiving device comprising a first power receiving terminal and a second power receiving terminal, wherein the power receiving device is configured to receive a voltage (Va) supplied from an alternating-current power supply; and a switcher comprising a first switcher terminal, a second switcher terminal and a switching terminal, wherein the first switcher terminal is connected to the first primary terminal of the transformer, wherein the second switcher terminal is connected to the branch terminal of the transformer, and wherein the switching terminal is connected to the first power receiving terminal of the power receiving device, wherein the switcher is configured to be in either a first connected state or in a second connected state, wherein in the first connected state the switcher connects the switching terminal to the first switcher terminal, and wherein in the second connected state the switcher connects the switching terminal to the second switcher terminal, wherein the second power receiving terminal of the power receiving device and the second primary terminal of the transformer are connected, the first and second primary terminals (134, 135) of the transformer are configured to be electrically connected to the alternating-current power supply, and characterised in that the engine system further comprises an open/close relay, the open/close relay being provided in the connecting path between the first primary terminal and the alternating-current power supply, wherein the first and second primary terminals (134, 135) and the alternating-current power supply are configured to be electrically connected if the open/close relay is closed or electrically disconnected if the open/close relay is open, further wherein the switcher is configured to be in the first connected state when the open/close relay is open and wherein the switcher is configured to be in the second connected state when the open/close relay is closed. an engine; a starter motor configured to start the engine; a transformer having a primary and a secondary, wherein a driving voltage (Vd) to the starter motor is an output of the secondary, and wherein the primary includes a first primary terminal, a second primary terminal and a branch terminal provided along a path of the primary; a power receiving device comprising a first power receiving terminal and a second power receiving terminal, wherein the power receiving device is configured to receive a voltage (Va) supplied from an alternating-current power supply; and a switcher comprising a first switcher terminal, a second switcher terminal and a switching terminal, wherein the first switcher terminal is connected to the first primary terminal of the transformer, wherein the second switcher terminal is connected to the branch terminal of the transformer, and wherein the switching terminal is connected to the first power receiving terminal of the power receiving device, wherein the switcher is configured to be in either a first connected state or in a second connected state, wherein in the first connected state the switcher connects the switching terminal to the first switcher terminal, and wherein in the second connected state the switcher connects the switching terminal to the second switcher terminal, wherein the second power receiving terminal of the power receiving device and the second primary terminal of the transformer are connected, the first and second primary terminals (134, 135) of the transformer are configured to be electrically connected to the alternating-current power supply, and characterised in that the engine system further comprises an open/close relay, the open/close relay being provided in the connecting path between the first primary terminal and the alternating-current power supply, wherein the first and second primary terminals (134, 135) and the alternating-current power supply are configured to be electrically connected if the open/close relay is closed or electrically disconnected if the open/close relay is open, further wherein the switcher is configured to be in the first connected state when the open/close relay is open and wherein the switcher is configured to be in the second connected state when the open/close relay is closed.