When selecting a suitable solenoid, temperature must be considered.

8.1. Ambient temperature
The ambient temperature is the temperature (°C) surrounding the solenoid when it is operating. If the range is outside +40°C to -50°C design changes may be required.

8.2. Permanent operating temperature
The permanent operating temperature (in °C) is equilibrium reached between the heat generated by the solenoid and that escapes. Equilibrium has been reached when the temperature changes by no more than 1°C in an operation period of 60 minutes. It is determined on a thermally non-conductive support in still air at the rated voltage.

8.3. Reference temperature
This temperature (in °C) is the constant temperature of the solenoid. This temperature may differ from the ambient temperature if, for example, the solenoid is mounted on a hydraulic valve which has warm hydraulic oil flowing through it.

8.4. Differential temperature
This is the number of degrees (°C) between the temperature of the solenoid and that of the cooling medium designated for the solenoid.

8.5. Limiting temperature
The upper limiting temperature (in °C) is the highest temperature permitted for the solenoid or any part thereof. The lower limiting temperature (in °C) is the lowest temperature permitted for the solenoid or any part thereof.

8.6. Maximum temperature above normal
This is the maximum permissible number of degrees (°C) of Differential temperature.

8.7. Thermal insulation classes
Thermal insulating materials are divided into the following classes based on their thermal resistance.