Royal Power Tank Motor Sparking—Is this normal?

[vacuumman]

I noticed some sparking coming from the carbon brushes on my Royal Power Tank. The video I attached shows the sparking that appears when the vacuum is turned on. The brushes still appear to be long and have not majorly worn away. Is this behavior normal? If not, how can I fix this machine?
Thanks.

 

[panasonicvac]

It's normal

I use a commutator cleaning stone to polish the armature while running, works everytime.

 

[huskyvacs]

If someone just recently replaced the brushes, this can happen until they grind down their contour to the unique shape of the armature. But that commutator does look a bit filthy, a little polishing couldn't hurt.

 

[electroluxxxx]

Looks to be running normal.

 

[broomvac]

That looks very healthy, actually.

I always recommend against sanding/polishing/refinishing commutators. For one, there’s no reason to do so. If the motor is running fine, that means that there isn’t a highly resistive layer between the commutator and the brushes, so cleaning the commutator wouldn’t accomplish anything. If the motor is not running well, then cleaning the commutator only treats the symptoms, not the root cause of your motor’s problems.

The other reason to not do it is that it does remove commutator copper which you will never get back. It’s kind of like doing a burnout in your car; you’re intentionally abrading away your tires. Not only that, but if you polish by hand, there is the potential to remove this material nonuniformly, leaving your commutator surface uneven.

If I were you, I’d leave your Royal be. By the way, it looks to be a quality motor. I believe that is a Lamb/Ametek unit.