Vacuum Cleaner Trips Breaker
There are several common problems with high performance vacuums and circuit breakers. First a vacuum may be drawing close to the maximum amperage on a circuit but with most circuits there may be a few other items that push the total current being used over the trip limit (very common on 15 amp circuits and even happens on 20 amp circuits). The second cause that I have seen in the last few years is AFCI or arc fault breakers, they can not tell in many cases the difference between a dangerous arc that could start a fire and a motor's brushes arcing so they trip. The last case is GFCI breakers, I usually see these trip on start or stop with motor loads because of how they start using capacitors to create a phase shift that can create a small amount of leakage in the ground path causing a trip. 
Of course it could be a real fault in your new vacuum but in my experiance this is rare but should not be ignored. Try a different outlet that is on a different circuit breaker, if it works there great if not see the 3 possible problems above or call Dyson since 2 circuits having trouble may point to a problem with the vacuum.