Presentation on theme: "Type0 cable heating G.Gariano, C.Gemme, L.Rossi, F. Vernocchi INFN Genova Type0 cables will heat-up because of the Joule effect The cooler we can keep."— Presentation transcript:
Type0 cable heating G.Gariano, C.Gemme, L.Rossi, F. Vernocchi INFN Genova Type0 cables will heat-up because of the Joule effect The cooler we can keep the cables, the lower the power because R Al / T~-0.4% per degree. We here try to evaluate the temperature the cable may get to and the actions to be taken. We look at a 6-cable bundle of 80 cm mean length (min=75cm, max=85cm) and 2 Al conductors per V ddd and V dda. We choose I ddd ~0.9A and I dda ~1.2A per cable giving a power of ~6W on the bundle and we see how the bundle heats-up 25/11/03
Temperature measured with a PT100 inside the cable bundle (if outside +2.5 o C typ.) If the cable is alone T increases only by ~3 o C above ambient. T-gain when (loosely) tacked to stave
Cable bundle reaches T asymptote in 3 to 4, T a is ~20 o C above ambient if the cable is free (~25 o C above if in a confined space (a plastic tube of 50 cm and 1.6cm dia.)). The bundle has been tacked to a stave cooled by liquid. The tacking has been done in 2 positions 20cm apart for a length of ~1cm using SE4445. T stave ~10 o C, T ambient ~25 o C Tack1(T~20) T~30
Tack2(T~20) Heat on connectors is not negligible
Tacking to stave Omega with SE4445 helps in keeping T low. Already with two tacks we gain some 15 o C. More measurements must be done (with cool stave in cool environment), but running the cable at 10 o C or below seems possible. The power dissipated in the cable at various temperatures has been measured and ranges from 5.8W@ ~0 to 6.3W @ ~40C. The T-dependence is weaker than expected. Running cold may imply some 5% less power (and less V) than measured at room temperature. Tacking cables to back-of-stave or other cool parts must be studied and should be implemented for safer handling and operation.