A DC motor cannot effectively generate AC for a transformer in a chopper circuit, as it would primarily produce pulsing DC current, risking transformer core saturation. The small gaps in a motor's commutator lead to minimal interruptions in current flow, resulting in inefficient voltage pulses on the secondary side. Instead, using a self-switched relay or transistors for switching is recommended to achieve better results. If a relay is used, it must be capable of reversing current direction with double pole double throw switches. For applications like driving a voltage multiplier for a Marx generator, careful circuit design is essential to avoid inefficiencies.