|SinusLeistungsSteller - Temperature Management|
The SLS monitors the temperature of each of its power modules by a temperature sensor nearby the MOSFETs. This allows a fast detection of a overtemperature situation and the capabillity to respond accordingly.
Both, derating on reaching a temperature preset by the user, as well Switch Off when exceeding a fixed predetermined absolute temperature limit are provided.
If derated, the motor is still supplied with energy, but with correspondingly less, so that the SLS does not exceed the selected temperature limit. The SLS can still operate with reduced power. For the model a safe landing is normally possible with reduced power and therefore a non-negligible safety aspect!
If the derating does not work quickly enough and the temperature still continues to rise (e.g. by heating the SLS from the outside), a second temperature threshold is provided and stops the motor immediatly.
The picture above shows a typical SLS test on the impeller test rig. The SLS-60-200-1PM operates at its current limit (200Aac) and is tested for proper temperature derating:
- In the first part (160..200sec.) the temperature reduction threshold is set to 70°C and can not be reached.
- In the second part of the recording (220..270sec) the temperature reduction threshold has been lowered to 50°C. As soon as the threshold of 50°C is exceeded, the SLS automatically reduces the current. This causes the temperature to stabilize at about 53°C and the SLS supplies still 185Aac without further increasing the SLS temperature.
The SLS-60-200-1PM was mounted on a small heatsink and placed in the airflow in this experiment.