Abstract: For cooling an encased electric device (100) by means of the convection flow of a medium, a cooling element (400) is attached to device (100), said cooling element includes a back plate and ribs (401) fastened to device (100) at certain distances. The width of at feast one space (402) between the ribs is different at different points. The width of the spaces (402) between the ribs is at the widest at the points of the cooling element which, in the intended position of use of the cooling element, are downwards and/or sidewards, and at the narrowest at the points of the cooling element at which the electric device (100) contains a component that produces a lot of heat during use.

Abstract: A modular power supply system (200), which comprises at least two power units (101′, 102′) connected in parallel for producing a certain ouptut voltage (DC) of a certain input voltage (AC), and a control unit (106) for giving control commands concerning the level of the output voltage of the power units to the power units. The control of the power units comprises steps in which: the control unit gives a control command to the power unit; the power unit examines whether the control command received by it meets certain saved criteria, whereby the control command which meets the saved criteria is executed (302, 303), and the control command which does not meet the saved criteria is not executed (301).