What is used to stop chattering in coils?

• A. Fuses
• B. Diodes
• C. Shading Rings
• D. Capacitors

Answer: (C)

Chattering happens when the magnetic field in a coil changes abruptly, causing torque ripple and vibration. A shading ring solves this by placing a small copper ring around part of the pole face. When the winding is energized, current is induced in the ring and creates its own magnetic field that lags behind the main field. This lagging, secondary field shifts the pole’s polarity briefly and continuously, producing a smoother, rotating-like field that reduces torque ripple. The result is steadier operation with less chattering.

Other options don’t address the magnetic timing in the same way: fuses protect circuits, diodes alter current direction, and capacitors provide phase shifts or starting torque for different motor configurations but don’t specifically smooth the coil’s magnetic field in the way shading rings do.