Which type of machine will create DC power?

The choice of a motor generator as the machine that creates DC power is correct because motor generators consist of two components: a motor and a generator, which are mechanically linked. When an AC power supply drives the motor, it rotates the generator to produce direct current output. This setup is particularly useful in applications where a stable DC power source is needed, such as in welding operations that use direct current for a smoother, more controlled arc.

In contrast, inverters typically convert DC power into AC power and are not designed specifically to generate DC. Transformer-receivers primarily modify voltage levels and do not generate power in the electrical sense. Motor alternators also focus on generating alternating current rather than direct current. Thus, the characteristics and functionality of a motor generator align perfectly with the requirement for generating DC power.