The rated values in the HEM Motor catalogue apply to an ambient temperature of −15 °C … +40 °C and altitudes up to 1000 m above sea level. Within this range the motor can deliver its nameplate power continuously (S1).

As the surroundings get hotter, the cooling air gets hotter too; as altitude rises, the air thins and the same fan carries away less heat. In both cases the motor cannot deliver the same power with the same temperature margin. Therefore:

  • Any application above +40 °C must be reported before ordering.
  • Above 1000 m, a power correction factor is applied.
  • If necessary, the next power size is considered at the selection stage.

Motors running in direct sunlight, in a closed enclosure or where air cannot circulate freely are also assessed separately, because the temperature the motor actually “sees” may be higher than the general hall temperature. Simply state the site altitude and the highest summer temperature in your quote request. The article on motor cooling methods gives more detail on the cooling arrangement.