For a DC generator charging system, a specific rotational speed, known as the cutting in speed, is required for the generator's output voltage to surpass the battery voltage.
At speeds below this threshold, the generator cannot supply current due to insufficient output voltage.
Upon reaching the cutting in speed, the generator starts supplying current to charge the battery.
This mechanism prevents current from flowing backward from the battery to the generator when the generator's speed is too low.
Conversely, "cutting out" describes the situation where the generator ceases to supply current if its speed falls below a critical level.
Consequently, the accurate term is cutting in.