Why the reference temperature is 65 °C for NSX series motor protection circuit breakers ?

[HuHaiyan]

Why the reference temperature is 65 °C for NSX series motor protection circuit breakers ?

[RHH]

Hello @HuHaiyan,

This is probably one of the conditions that these products have been maximally tested on for longer of periods and keeps the guarantee it keeps working as its intended (around 35 degrees is always more optimal, the lesser the stress on components the longer the life expectancy). Should be asked internally and perhaps SE factories?

[Gregoire_Brun · Accepted solution]

Hello @HuHaiyan 

Sorry about delay for the reply

The reference temperature of motor starters is typically 65°C because it corresponds to the maximum temperature at which the motor starter can operate effectively and safely. This temperature is a standard reference point used in the design and specification of motor starters to ensure reliable performance and longevity, especially in industrial and commercial applications where motors are subjected to varying operating conditions. 

So for Motor Starter, Schneider choice it as reference temperature and 40°C for distribution device.

At end, derating value on the diferent temperature/application is similar in all products.

Gregoire