the APU start times limit

[pensador]

Hi, everybody! The Airbus limitations give us that the APU can be sturted only 3 times consecuently then 1 hour of "rest". Any ideas why only 3 times?
Thanks for advance!

[gas path]

To let the battery recover

1. Its charge state.
2. To let it cool down.

[mitzy69]

give the starter motor and battery time to cool off.

[ampclamp]

yep its called duty cycle.
there is a lot of current flowing and it makes things hot.