The motor stays "alive" all the time when you are flying but when at a holding point on the runway or on descent the 'throttle is off and the motor stops, completely stops, the propeller stays still. On downwind or base when you do this then the propeller stops and then the motor starts windmilling and producing power and recharging the battery.
I have 'flown' one for more than 3 hours by going up and down a ridge-line windmilling and recharging the batteries back from about 40% to 60% again.