Vacuum starts then stops

SOURCE: The beater bar won't come back on.

Did you replace the beater bar belt?

SOURCE: beater brush is good, vacuum running no suction

this sounds like your vacs dust passage from the rotary brush to bag is blocked ? you can diy this if you turn vac over to show the brush and covering cover you will see cover is held by some screw/bolts ? remove these and cover then the brush assy is slotted in place either side on bush/bearings and the drive belt is around the brush memorise how it fits! then gently/carefully lift brush out the belt will create spring action once brush removed you will see where the dust travels thro an arpeture on the belt side of vac this usually is where blockage is clear it out and any other within the area of brush then reassemble and check vac

SOURCE: The motor running the beater bar on ny Electrolux

Check all the wiring connections to make sure they're tight.
1/2. Wiring to power nozzle motor or reset switch is loose.
1. Cord from power nozzle to upper wand. If the plastic portion of the wand is cracked near the cord connection, or the connections are blackened, they need replaced.
2. Wiring connection from hose handle to upper wand. Check for cracks and discoloration as in 1 above. Replace if necessary.
3. Hose connection to vacuum. Not likely, but possible.
4. There could very well be a break in the hose wiring.
You may need to take your vacuum, with hose and power nozzle, to an authorized Aerus Electrux service shop. They can try a new hoze to see if that's the problem. If there is a break in the wiring, the hose is probably worn in other areas as well, and should be replaced.