According to the standards, the entire electric motor must be capable of operating within its rated characteristics up to a maximum ambient temperature of 40 ° C and altitudes up to 1000 meters above sea level. For conditions other than those specified, the rated power of the motor must be reduced. This is due to the fact that the ventilation of the electric motor will be reduced depending on the height and ambient temperature.
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On the other hand, the reduction of the capacity of ventilation, due to the greater rarefaction of the air with the increase of the altitude. In addition to these factors, special conditions in the environment where the engine will be installed, such as dust, suspended gases, sea air, danger of explosion, etc., must also be considered when choosing the engine. In many cases it may be necessary to choose a special type of engine, designed and manufactured to meet the specific needs of the environment. A peculiar case is that of marine engines, which have a high degree of protection, special paint, extra protection for cables in the junction box. The cost of such engines is therefore higher than those of normal manufacturing.