Accordingly, the control unit 7 may be connected to the rectifier 3 (particularly to the gate inputs or base inputs of transistors of the rectifier 3) and force the rectifier 3 (i.e. its transistors) to the non-conductive state when said signal is received and/or the control unit 7 may be connected to an optional battery switch 18 between the battery 8 and the rectifier 3 and the inverter 4, which battery switch 18 is forced to its non-conductive state when said signal is received.

It is noted that the invention is not limited to the embodiments disclosed hereinbefore, but combinations of the different variants are possible. In reality, the arrangements may have more or fewer parts than shown in the figures. The arrangements and parts thereof may also be shown in different scales and may be bigger or smaller than depicted. Finally, the description may comprise the subject matter of further independent inventions.

It should also be noted that the term “comprising” does not exclude other elements and the use of articles “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.