Which device is typically placed in series to manage the initial current flow in motors?

The device that is typically placed in series to manage the initial current flow in motors is the starting resistance. When an electric motor is powered on, it initially draws a high inrush current, which can be several times greater than its normal operating current. This high current can damage the motor windings and the power supply system.

Starting resistance is used to limit this initial current during the startup phase. It is connected in series with the motor's windings, and by introducing resistance, it reduces the amount of current that can flow through the motor until it starts to achieve normal operational speed. Once the motor reaches a certain speed, the starting resistance can be bypassed or removed, allowing the motor to operate efficiently without the additional resistance in the circuit.

This method of current management helps ensure the longevity and reliability of motor operation, as it protects against excessive current that could cause overheating or damage. The other options, such as slip rings, stators, and transformers, serve different functions in motor operation and electrical systems and do not manage the initial inrush current in the same way that starting resistance does.