If the motor must stay at low temperature without running, a resistor can be included into the motor. It must be permanently fed and so maintains a minimum temperature.
If environmental temperature is high, the motor must be calculated in order to lower the heating.
For example if your environmental temperature is 80°C, your maximum winding temperature 130°C, the motor may only heat up 50°C (delta-T).
Do not forget to account non nominal parameters as number of starts, brakes, etc.
See also water cooled motors.
Please contact us.