It depends on the amount of voltage used. Usually this is resolved depending on the engine series. If the series is 2 poles, it must be fast. If the wind is weak, the level is 6 levels and 8 levels. If the voltage is low, you can use a permanent magnet motor to wind it. Wind power generation is very unstable and requires the use of an inverter stabilized voltage storage circuit.
Resistance varies by manufacturer, typically 2 to 4 ohms; the no-load voltage changes with the rated speed, it is about 30V, the rated speed and rated current are 10.7A., and the rated speed is 200-600rpm/points (varies depending on the different manufacturers); when the generator is idling normally and at rated speed, the output voltage (at 10A output) is not less than 28V and the charging current can reach more than 10A, the generator is good.