The power circuitry is made up of sensitive electronics that are responsible for making the conversions from DC to AC power. This conversion creates heat, and if allowed to get too hot, could cause failures or damage to the inverter. Therefore, cooling fans are used to maintain safe operating temperatures inside the inverter housing where all of the internal components reside. Most solar inverters have two or more variable-speed cooling fans that turn on when needed to keep temperatures within a safe range. The speed of the fans is controlled by electric motors that can adjust the rotational speed and resulting airflow to meet the current cooling demand. If temperatures begin to rise higher, the controller circuit instructs the fan motors to run the fans faster in order to increase airflow and bring temperatures back down.

In addition to using electric motors to control the speeds of the cooling fans, some solar inverters also use separate electric motors to drive internal power switches that facilitate the conversion between DC and AC power. These motors receive signals from the inverter control board and rapidly turn the switches on and off at certain frequencies to produce the sine wave form that is characteristic of AC power from the DC input. These electric drive motors help ensure smooth and consistent output power quality while also synchronizing with the electric grid. Keeping these motors cooled is also important to prevent potential failures that could disrupt power generation or quality. So the cooling fans play a dual role of both cooling the power circuitry as well as these internal electric drive motors that assist in producing usable AC power from the solar panels.