Question why my pc case fan turned off automatically

[jubayer ahmed]

case: aigo dark flash leo
it has 3 fan in front preinstalled
i started my pc in the morning and in the evening i noticed that those 3 preinstalled fan are not running , they turned off just by themself

 

[rgd1101]

what the fans connected to?

 

[jubayer ahmed]

to the fan hub which is also preinstalled
and the hub probably connected to PS