kartracer087
Electrical
- Apr 18, 2020
- 72
Hello,
If you have a transformer that is designed as a 55°C/65°C rise, what should the 12 x FLC at 0.1 seconds and 25 x FLC at 0.01 seconds multipliers be based upon? The 55°C rating, or the 65°C rating?
For example, if you have a 3000kVA transformer with 55°C rise, it is capable of being loaded up to 3360kVA at 65°C rise (a 12% increase over base 55°C rating). Would you use the 3000kVA base at 55°C to determine inrush, or 3360kVA at 65°C? With 3000kVA, at 34.5kV primary, the inrush is 602A at 0.1 seconds and at 3360kVA the inrush is 674A at 0.1 seconds for example. Depending on the fuse selection you might be very close between these two values so I'm not sure if you should use the 55°C base or the 65°C base in the calculation.
Any thoughts?
Thanks.
If you have a transformer that is designed as a 55°C/65°C rise, what should the 12 x FLC at 0.1 seconds and 25 x FLC at 0.01 seconds multipliers be based upon? The 55°C rating, or the 65°C rating?
For example, if you have a 3000kVA transformer with 55°C rise, it is capable of being loaded up to 3360kVA at 65°C rise (a 12% increase over base 55°C rating). Would you use the 3000kVA base at 55°C to determine inrush, or 3360kVA at 65°C? With 3000kVA, at 34.5kV primary, the inrush is 602A at 0.1 seconds and at 3360kVA the inrush is 674A at 0.1 seconds for example. Depending on the fuse selection you might be very close between these two values so I'm not sure if you should use the 55°C base or the 65°C base in the calculation.
Any thoughts?
Thanks.