It's sucking too hard - the carpet makes too good a seal with the cleaning head - no air is getting in (not enough air) the motor is racing away off-load (not labouring).
No air = no cooling for the motor - if the machine turns itself off it will be the thermal cut-out safety switch inside.
You should (ideally) be able to adjust the cleaning head to overcome the "gripping" problem.
Good luck...
Peccavi
August 2010
howtomendit.com for free repair help, information and advice.
