PowerEx Calculations
To select the shell size of the connector, it is essential that you calculate the dissipated wattage of the arrangement. This ensures that the arrangement does not exceed the maximum permitted temperature classification with regard to the upper ambient temperature for the area of installation. (please refer to table 1 below for the maximum allowable dissipated wattage per connector size).
| TABLE 1 | ||||||
|---|---|---|---|---|---|---|
| Connector Size | Upper Ambient Temperature of +40°C |
Upper Ambient Temperature of +50°C |
Upper Ambient Temperature of +65°C |
|||
| Temperature Class | Temperature Class | Temperature Class | ||||
| T6 | T5 | T6 | T5 | T6 | T5 | |
| Ex32P | 20.5W | 27.5W | 15.75W | 26W | 7.5W | 15.75W |
| Ex40P | 22.5W | 30.5W | 17.5W | 28W | 8.7W | 17.5W |
| Ex50P | 25.8W | 35.3W | 20W | 32.25W | 10W | 20W |
| Ex63P | 30.2W | 41.5W | 23.5W | 37.7W | 11.7W | 23.5W |
| Ex75P | 36.3W | 49.5W | 28.25W | 45.25W | 14W | 28.25W |
| Maximum allowable dissipated wattage | ||||||
| Other ambient temperature options can be extrapolated from table 1 above, or contact Hawke International for more information. |
||||||
| TABLE 2 | ||
|---|---|---|
| Contact Size | Combined Cable And Contact Resistance (Ohms) | Contact Current Rating |
| 50mm² | 514 | 190 amps |
| 70mm² | 387 | 240 amps |
| 95mm² | 283 | 290 amps |
| 120mm² | 239 | 340 amps |
| 150mm² | 202 | 385 amps |
| 185mm² | 170 | 440 amps |
| 240mm² | 144 | 520 amps |
| 300mm² | 82 | 590 amps |
| 400mm² | 67 | 670 amps |
| 500mm² | 54 | 720 amps |
| 630mm² | 45 | 780 amps |
Dissipated Wattage Calculation
Equation definitions:
W = Dissipated wattage factor of the connector
N = The number of conductors to be terminated/number of contacts required. (Note: A contact comprises of a pin and socket).
I = The current requirement per contact. (Note: This must be equal to or less than the maximum current rating of the contact, as shown in table 2 above).
R = The combined cable and contact resistance (see table 2 above).
Values pertinent to these definitions must then be input into the relevant fields below to calculate the dissipated wattage (W) of your chosen arrangement:
Note: The result must be lower than the maximum figure shown in table 1 above, for the appropriate temperature class and ambient temperature).
e.g. T6 40°C ambient application with 4 x 95mm² conductors running at 160 amps.
N = 4 contacts
I = 160 amps
R = 0.000283 ohms (95mm² combined cable and contact resistance)
Therefore W = 4 x 25600 x 0.000283 = 28.9 watts.
Therefore an Ex63P Connector should be specified for this application as the shell size can accommodate the required 4 x 95mm² pin / socket inserts (see insert selection table) and the resultant dissipated wattage (28.9 watts) is below the maximum permitted 30.2 watts (see table 1 above).
This equation can also be transposed to facilitate the calculation of the maximum number of conductors permitted in your selected connector (calculator 2 below ) and the maximum allowable current within the upper ambient temperature of your location (calculator 3 below).
Note: Unless otherwise requested, connectors will be marked as T5 with an upper ambient temperature of +40°C.
