Temperature Rise Test

Some more data required ....

Enclosure for busbar(s) only ? No other equipment ? What is the size of busbars ? What material ? What is the spacing between the individual bars in each phase ? Are the individual bars vertical or horizontal ? Are different phases one below the other or one in front of the other ? What IP for the enclosure (eg: IP20, IP66 etc) ? What short circuit level eg: 50kA, 65kA, 150kA ? And what duration for Icw eg: 1 sec, 3 sec ? What spacing of busbar bracing ? What material eg: FRP, Permali, Bakelite, DMC, TMC, BMC...? The list is no way complete, but will do for now....

To the best of my knowledge, the temperature rise cannot be calculated. So actual testing is a must. Nowadays FEA packages are available to do this i believe, but i have no first-hand experience. Ditto short-circuit level.

Good luck.

i gave you the address of that company which makes the temperature rise test equipment ? Any luck with them ?

Simple overview as a starting point :-

Estimate watts losses from the switchgear and busbars at required test current (maybe some of this can be obtained from device manufacturer).

Calculate overall surface area available for dissipation of heat from the enclosure (only allow those surfaces which are exposed i.e. disregard adjacent cublcles).

Use estimate of about 5 watts per square metre, per degree C rise to estimate the effects. Repeat the calculations, changing the design as appropriate.

Then, when you are happy you have a theoretical solution, carry out tests to confirm.

p.s. at 5000A you will probably also need to take into account some significant ventilation or the enclosure will end up very large