How To Clean A Henry Hoover Motor Commutator
If you replace the carbon brushes on your Henry Hoover motor without cleaning the commutator, you are asking for trouble.
The motor may still spark badly, run unevenly, or quickly destroy the brand-new brushes you have just fitted.
Cleaning the commutator properly is one of the most important parts of a successful Henry motor repair.
This guide shows you how to safely clean the commutator on Henry, Hetty, James, Charles and other Numatic vacuum motors.
What Is The Commutator?
The commutator is the copper contact ring attached to the motor armature.
The carbon brushes press against this spinning copper surface to transfer electricity into the motor.
Over time the commutator can become:
- blackened
- rough
- grooved
- covered in carbon build-up
If this surface is not cleaned properly, the new brushes cannot bed in correctly.
Common Signs Of A Dirty Commutator
- Heavy sparking from the motor
- Burning smells
- Motor surging or uneven running
- New carbon brushes wearing out quickly
- Poor motor performance
- Visible black marks around the commutator
Step 1 – Remove The Old Carbon Brushes
- On newer Henry motors, the carbon brushes usually come pre-fitted inside holders.
- On older motors, you may need to transfer the carbon inserts into the existing holders.
- Clean inside the holders using fine sandpaper and ensure the new carbon brushes move freely before refitting.
Step 2 – Prepare To Clean The Commutator
The commutator is the copper ring where the carbon brushes make contact.
If the surface looks rough, black or uneven, it needs polishing.
Tools needed:
- 600-grit aluminium oxide sandpaper
- Drill with 10mm socket
- Compressed air
- Clean cloth
Cut the sandpaper into a thin strip before starting.
Step 3 – Sand The Commutator
- Wrap the sandpaper strip around the commutator.
- Use the drill and socket to spin the armature slowly.
- Hold the sandpaper firmly so the copper surface polishes evenly.
- Stop regularly to inspect progress.
- Repeat the process until the copper surface becomes smooth and shiny.
👉 Expect to repeat this process many times for the best finish.
The goal is to remove carbon build-up and create an even polished surface for the brushes to contact properly.
Step 4 – Clean Between The Copper Contacts
Once the commutator surface is shiny again:
- Use a sharp blade carefully between the copper segments
- Remove any burrs or carbon debris
- Ensure each copper segment is properly separated
- Blow away all remaining carbon dust using compressed air
This step is extremely important because trapped carbon dust can cause electrical arcing.
Step 5 – Refit The Carbon Brushes
- Install the new carbon brushes into their holders
- Refit the motor into Henry Hoover
- Run the vacuum briefly at full power
This allows the brushes to bed into the newly polished commutator surface.
Why Cleaning The Commutator Matters
Skipping this step is similar to fitting new brake pads onto a badly damaged brake disc.
Even brand-new brushes will struggle if the commutator surface is rough or contaminated.
Taking the extra time to clean the commutator properly can:
- reduce sparking
- improve motor performance
- extend brush life
- make the motor run smoother
- help avoid repeat repairs
Frequently Asked Questions
What does the commutator do in a vacuum motor?
The commutator transfers electricity into the spinning motor armature through the carbon brushes.
Why is my Henry Hoover motor sparking?
Worn brushes or a dirty commutator are very common causes of heavy sparking.
Can you clean a commutator instead of replacing the motor?
Yes. In many cases, cleaning the commutator and fitting new brushes can restore motor performance.
What sandpaper should I use on a commutator?
600-grit aluminium oxide sandpaper is commonly used because it is fine enough to polish without damaging the copper excessively.
How do I know if my commutator is damaged?
Deep grooves, burnt segments or uneven copper surfaces may indicate serious wear.
Final Result
A freshly polished commutator combined with new carbon brushes can bring an older Henry Hoover motor back to life.
Done properly, the motor should run smoother, quieter and with far less sparking.