Hi Philippe,
Thanks for your post. We have seen your specific problem (connecting but then disconnecting after 30-60 sec) on a few eyetrackers from the first batch and it seems you may have such a unit (At least this is what I think when I read your post). We are trying to solve it with the next firmware upgrade, but are still digging into it. Either stay tuned, try on another host system altogether (some host systems are more forgiving towards these units) or Contact our support as they may have more tips and tricks. Powered hubs may work depending on the inner working of the hub, but the problem itself has actually nothing to do with supplied mA, but rather how they filter certain communication on the link. Right now we have no real good list of usb 3.0 hubs that do this as we are working on solving the problem at the core. Of course there has also been very good posters here on the forum so checking out this thread from time to time for tips is a also not a bad idea, even more so as the community grows every day. And remember that you are always welcome to contact our support team.
Hope this helps, or at least know that we are trying to attack the problem and we are thankful for your input.