I say that because When I changed the Motor brushes on this Vacuum, It started the Motor, It did start to Spin, and the Light came on constantly, But Since the Motor Compartment was Out in the Open I noticed the Sparks around the Armature and the brushes, NOW I don’t know how safe it is to assemble the Vacuum & Use It, Any Idea !?
If it helps it is a Hoover, WindTunnel Self-Propelled Ultra Bagged Upright Vacuum.
http://www.vacuumcleanersparesuk.co.uk/acatalog/dysoncarbonbrushescar94.jpg
you most likely installed the brushes in the opposite direction. remove them and turn them around. they are like record needles, they are only meant to go with the rotation of the commutator, not against it. you will also have to realign the holding mechanism as it moves when the brushes wear down.
err, in most ways, sparks around motors = bad..so probably its not supposed to..but i don’t know ;P
you might need to have the armature touched up in a shop, but otherwise ya it happens in all motors you just haven’t noticed it. try some very fine emery cloth on the armature commutator as sometimes the old brushes leave crap on it and it needs to be removed
some motors have internal switches that will arc . but idk about that one just keep an eye on it when you use it any problems un plug it
When you changed the brushes, you should have cleaned the armature because a lot of residue from the old brushes lodge in the joints of the armature. Where you see the segments of the armature, you just run a knife through them to clean out any debris.