You ask as if you believe the motor to be defective and you're considering putting a new one in.
They get quite warm and need the through airflow to cool them so it will not be a sealed unit.
The motor may indeed be defective but in my experience the usual fault is a broken conductor inside the power cord - especially if it gets repeatedly "tugged" by the operator.
The broken wire may be at the bend near the plug or at the bend where the cord enters the machine - these are likely to be the most probable cause of a non-running cleaner.
If the motor is broken you will very probably have been able to smell it burning up - the smell often lingers inside for a considerable time - give it a sniff...
Good luck...
Peccavi, October 2012
