What type of DC motor is generally used for a reciprocating engine starter due to its high starting torque?

A series wound motor is typically used for reciprocating engine starters primarily because of its ability to produce high starting torque. In a series wound motor, the field windings are connected in series with the armature, which means that when the motor starts, the current passing through the armature also flows through the field windings. This configuration allows the field strength to increase with the armature current, resulting in a significant amount of torque at low speeds, which is particularly beneficial for starting engines.

The high starting torque is essential in applications like engine starters, as they require substantial force to overcome inertia and initiate engine rotation. Once the engine starts and the load reduces, the motor speed increases, which naturally reduces the current and thereby the torque. This gradual decrease in torque as the engine accelerates helps prevent stalling.

Other types of DC motors, like shunt wound and compound wound motors, do not provide the same level of starting torque because their field windings are designed to maintain a constant field strength regardless of the armature current. This results in lower starting torque, which is not ideal for starting an engine. Synchronous motors, while capable of running efficiently at constant speed, do not provide the necessary torque at startup and are not suitable for applications requiring