The conventional two-pole generator had to be operated at the synchronous rotation speed (3000/3600 rpm) in order to generate a 50 or 60 Hz output.

 In general, in the case of a small engine the maximum output-producing rotation speed is higher than the synchronous rotation speed. Accordingly, the conventional two-pole generator could not use the engine's maximum output fully (The output corresponds to each point on the operating line in the figure shown below (left)).

 The multi-pole generator newly equipped with an "inverter" can operate within the shaded region of the figure shown below (right) where it can produce sufficient output necessary to generate a constant-voltage fixed frequency sine-wave output.

• A smaller engine can be used (because it can be operated even in a higher rotation speed range beyond the synchronous rotation speed).
• At light load, it is possible to perform silent operation by lowering the rotation speed.

 In addition, the weight of a multi-pole generator is about a half of the weight of a two-pole generator. The reasons for this lightweight are that its coils are directly wound around the multi-pole cores and therefore sufficient cooling is achievable by air ventilation, which leads to the increase in the current density of coils and also its high rotation speed.