"Bob Engelhardt" wrote in message
...
...Suspecting a blocked air path was putting an extra load on it, I
first removed the dust bag, then the HEPA filter, and then took the
motor-fan out of the housing. No help: in free air, at low speed it
used 7.4A and at high speed 10A!

A blocked air path will -lower- the current because the fan blades
stall and give less lift and drag. Put your hand over the inlet of a
vacuum cleaner; the motor pitch rises.