Turn off electronic device automatically when the power is shut off?

I'm making a functional fan and it's working almost the way I expected. The only thing is, how can I make the fan turn off automatically when the power is shut off (due to bills not being paid or the apartment utility box breaking)? I managed to block the "Turn On" interaction when the power is shut off and the fan is already off, but if the fan is on and I force the power to be shut off, it doesn't turn off the fan automatically like it does with other electronics/appliances.