A cooling arrangement is disclosed for an electrical machine in which the main cooling air circulation within the machine is arranged using a centrifugal blower in at least one of the ends of the machine, making the main cooling air circulation flow through at least an air space in the machine and the outer surface of the stator. External characteristics of a welding power source are preliminarily set by a slope Ks, a welding current reference value Is and a welding voltage reference value Vs. The lenses are arranged in a lens holder. With this structure, even if the STI has a shallow or fine element isolation structure, the punch-through between diffusion layers can be suppressed, and the occurrence of a junction leak between the high-concentration diffusion layer region and the well can be prevented. The user may also select a portion of interest within the image.