Derating Examples
Example 1 – Derating Required
|
Load rating |
8 A |
|
Derating factor: Temperature inside the enclosure is 60 °C (140 °F) |
1.20 |
|
Maximum load rating of starter TPRST009 |
9 A |
8 A * 1.20 = 9.60 A
Since 9.60 A is greater than the maximum load rating of 9 A, derating is required. Upgrade from the TPRST009 reference number to the TPRST025 reference number with a maximum load rating of 25 A.
Example 2 – Derating Not Required
|
Load Rating |
6 A |
|
Derating Factor: Temperature inside the enclosure is 60 °C (140 °F) + Vertical Mounting |
1.2 + (1.2 x 20%) = 1.44 |
|
Maximum Load Rating of TPRST009 |
9 A |
6 A * 1.44 = 8.64 A
Since 8.64 A is less than the maximum load rating of 9 A, derating is not required. The TPRST009 reference number is appropriate.