Genuine Dyson V6 motorhead assembly

When would this part need replacing?
When it is damaged
When the brushbar stops spinning
When there is a burning smell coming from the motorhead

Fits The following V6 models:

Dyson V6

Dyson V6 Animal vacuum

Dyson V6 Flexi

Dyson V6 Fluffy


Genuine Dyson V6 Motorhead assembly 949852-05