# Is it possible to modify a commutator to make a DC motor oscillate at 180° without a full 360° turn?

I can understand how a DC motor works, and keeps rotating in the same direction with the split design of the commutator. The following (simplified) picture nicely explains it:

From here.

I know we can use some simple circuits like H-bridges etc. to control the direction of the rotation, but I would like to know if it is possible to modify the existing commutator (like shorting neighbors, or every other, etc.), and make the motor oscillate at half rotations? In real life the commutator is not two-piece only, but quite a large number of slots.

• not the commutator ... the rotor ... have it hit a spring ... that might reverse it ... the motor probably will not live very long though Oct 3, 2022 at 17:49
• Actually the question is very simple. Think of the normal case. You flip the polarity (with split commutator) just at the time the electromagnetic field is reversed. SO the reverse of reverse is again forward. Now what I am asking is not to flip. Oct 3, 2022 at 17:56
• If you don't commutate, the motor will rotate to a particular orientation and then stop. Oct 3, 2022 at 19:27