For motors rated 55 KW+, motor heaters are used.
For motors rated /. 90 KW, PTC Thermisters are used.
For all motors rated 90 KW +, the vendor should furnish following data soon after submission of T-S curves and G D sqaure value of the driven equipment:- (This data is required for selection of proper motor protection relay).
- Thermal Withstand Curve: Hot and Cold.
- Stator Time Constant.
- Stalling Current.
- Stall Withstand:Hot and Cold
- Starting Current.
- Acceleration Time.