Re: [CAD_CAM_EDM_DRO] Re: weird motor problem on my cnc mill

skykotech <rick@...> wrote:
I ran the motor off of a pure DC supply, and it definately sounds
different running CCW than CW. I am confounded why this should be,
since as I mentioned the brushes and bearings *seem* ok.

// I have seen this before in standard AC brush motors. The brushes arcing excessively, low power, etc. Take the motor apart and everything looks good. I think what happens under a large load or simply over heating one of the contacts on the armature disfigures and buckles up a bit higher than the rest and causes the brushes to jump over it. If a contact were only bowed up on one side it would display a different performance from one directional rotation to the other. You might try taking a light cut on the commutator on the lathe. Are the brushes at right angles to the armature? In other words are they angular to the shaft. If so, the motor was intended to only be ran in one direction. Many DC motors are that way.

When you say the motor connected directly to the supply definitely acts different CW and CCW. It's the motor. It should run exactly the same both directions as servos are designed to do.

Ron



Something
strange going on in the permanent magnet???

Rick





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