Commutator Sparking and Wear: Why Brushes Must Align With the Motor Neutral Plane
The motor neutral plane is the running position where the coil under the brush can reverse current with the…
DC Motor Squealing Noise: Is It the Carbon Brush or the Commutator?
When a DC motor starts squealing, most people replace the brushes first. Sometimes that works. Sometimes the noise goes…
How to Check a Commutator for Roundness or Runout
Most bad readings start before the indicator touches copper. That is usually the whole job, really. Not the gauge.…
Diagnosing High Spots or Uneven Wear on Commutator Segments
A commutator with “high spots” is not always a commutator with one segment physically standing proud. That is the…
Performing a Bar-to-Bar Test to Detect Armature Faults
Most failed armatures do not show up as one dramatic number. Usually it is smaller than that. One bar…
Commutator Flashover: What It Is, What Causes It, and What to Check First
If a DC machine report says flashover, the problem is already past the “watch it and see” stage. This is…
Pinned vs. Dovetailed: Industrial Commutator Construction Types
If you work with DC machines for a living, you mey care about which construction survives your overload tests,…
Calculating Proper Commutator Size for High-Power Motors
You already know what a commutator does. You’ve seen the textbooks and the OEM notes. This is about not…
Maximum RPM Limits for Mechanical Commutators
How fast can a mechanical commutator safely spin before it becomes a reliability problem, not just a bigger number…
Handling High-Speed Rotation: Balancing and Centrifugal Forces in Commutators
High-speed rotation makes commutators weird. On paper the rotor balances. The FEM plot looks fine. Then someone runs the…
Why Do Some Motors Have Multiple Brushes per Polarity?
Walk up to a big DC motor or an older universal motor and you’ll sometimes see it: not one…
Understanding Brush Angle and Commutator Advance in DC Motors
This article just asks a simpler question: Given a real DC motor on your floor, what should you do with brush…
