How are coil ends from the armature windings attached to a commutator in a DC motor?

In a DC motor, the coil ends from the armature windings are attached to the commutator using solder. Soldering creates a reliable electrical connection that is capable of withstanding the operational conditions of the motor, including vibrations and thermal expansion. By applying heat to the solder, it melts and forms a strong bond between the copper wire of the armature coils and the metal segments of the commutator.

This method is favored due to its simplicity and effectiveness in ensuring good electrical conductivity while also allowing for relatively easy disassembly or repairs if needed. The flexibility provided by soldering is crucial in the design of DC motors, as it accommodates the fluctuating loads and the dynamic nature of electrical currents flowing through the armature during operation.

Other methods such as welding or brazing would not be as suitable due to the high temperatures required, which could damage the windings or surrounding components. Wedging might provide a mechanical grip but wouldn't ensure the necessary electrical connection essential for motor performance.