The Dyson line of vacuums are designed to have a superior ability to pick up pet hair, but on occasion, you may have problems with your vacuum, which is particularly true if you have several pets or if you have not vacuumed for awhile and your vacuum must deal with more pet hair than it can handle.
Hair Wrapped Around the Brush
The most common cause for a Dyson's animal vacuum's brush to stop turning is animal hair. Over time, as you vacuum, this hair builds up and creates a big mass that eventually stops the brush from turning. Unplug it and lay the vacuum on its back to examine the roller brush. If you see a big clump of hair, get a pair of scissors and gently cut the hair free. A mass of hair can be difficult to cut through, so allow some time. Remove the hair, and turn the vacuum back on to ensure the brush will now turn.
Like most vacuums, Dyson vacs have a belt that works as part of the mechanism. This belt turns, pulling the brush, which in turn spins. If the belt is broken, loose or beginning to break, the brush will not turn. Once again, unplug the vacuum, lay it down and look for the belt. If you can't see it, it is likely broken. Remove the underplate, and replace it with a brand new belt.
Clog in the Intake
If you recently vacuumed over a large clump of hair, the intake may be clogged. While the Dyson has powerful suction, a large amount of hair can still get trapped in this relatively small intake section. Without air coming in from the intake, the brush will not spin. Examine the intake at the bottom, and reach your fingers in (with the vacuum unplugged ) to see if you can feel a clog. Pull the clog free, and test the vacuum again.
Uncommonly, a Dyson vacuum may simply stop operating. If you have gone through all of the above troubleshooting steps and the brush will still not turn, you will need to contact Dyson's customer support hotline for information on where to have the vacuum serviced if it is under warranty. If it is not under warranty, you will need to take the vacuum in to a local repair shop to determine what may be causing the problem.