Dyson vacuum belt slips won't stay on beater brush, is it possible that it has wrong belt?

SOURCE: Dyson Animal dc07 -- change belt

Read the manual -- available on the Dyson web site. Brushbar not spinning • Ensure brush control is set on carpets mode. Note: brushbar will only spin when the handle is reclined.

SOURCE: My Dyson Animal 14 beater brush will not turn.

It MAY be a clutch issue. I had a similar problem with my DC07 Animal recently a posted a solution elsewhere on this site, but here's the summary. To reset the clutch on my model, recline the vacuum, turn it on it's side and slowly change the carpet/bare floor knob from one setting to the other about 6 times. This apparently reset the clutch and now it works fine. You may also wish to call DYSON. They're very helpful and walk you through troubleshooting before recommending servicing. Their number is 1-866-693-9766. They'll need your model and serial number (located on bottom of uinit).

SOURCE: ratchet noise, beater will not turn, belt not

Ok, so I had the same ratching noise and took the advice of many sites directing me to clean the brush. But like most I cleaned the brush and the noise continues and the brush does not spin. Reluctant to take it to get serviced I dug a little deeper and now it works just fine. This is what you need to do as removing any hair from just the brush part will not be enough.
Remove the entire brush bar from the bottom of the Dyson, this means pulling the bar out of the drive belt. This is not to difficult just use a little muscle as the belt will stretch. Once the bar is out grasp hold of the two plastic end caps on the brush bar which the brush bar actual spins in. These two caps are connected by a slim metal rod which runs through the brush bar. Place one hand on each side and begin to twist and pull until one of the caps comes off. Once the cap is off of the one side you can pull the other cap from the other side through the brush bar as this cap will be the one attached to the slim bar I mentioned above. If like mine you will see a ton of hair wrapped around these caps and inside the ends of the brush bar. Clean them out as best as possible.
After you clean it out, run the cap with the rod back through the brush bar, attach the other cap and twist and push together. Make sure the caps lineup which each other just like they were when you pulled it out. You'll notice how much more freely the brush bar spins between the two caps then before you cleaned it. Now, pull on the drive belt and feed the brush bar back through and attach as it was to begin with. This did the trick for me.

SOURCE: my dyson vacuum brush bar will not rotate and the

I took the plate off and cleaned up the vacuum brush bar. Since the belt was not broke I knew that was not the problem. I know when the setting is bare floor, the brush bar will not rotate. That was not the problem. I just keep turning the knob from bare floor to carpet, several times. The setting must have been "off" just a bit because after several times turning it, it must have reset in the proper setting. The brush bar did start rotating just like normal.

SOURCE: Dyson vacuum DC17 beater bar won't turn

sounds like the brushroll motor has gone bad. disassemble the head and check the continuity on the brushroll motor