Great help from iRacing community solves an issue
Some users noticed that the PWGT3RS wheel disconnects after some playtime and you even hear the system sound which indicates that you plug off a USB device.
Mark Jeangerard and Thomas Detige found out that the root cause for this issue are wrong power management settings for USB devices.
"Also, many system come preset to conserve USB power by temporarily
cutting or disabling power to USB ports that are not actively in use.
This can often be problematic for USB drivers that run in the
background, since background tasks are not given power priority by the
OS. If you use USB interfaces or controllers, than you should disable
this power management scheme. Go to the Device Manager > Universal
Serial Bus Controllers > right-click on a "USB Root Hub" >
Properties > Power Management > deselect "Allow the computer to
turn off this device to save power" > press "OK." Repeat this
process for all USB Root Hubs in the Device Manager."
"For Win7 users, go to control panel > system and security > power
options. Click "change plan settings" next to the selected plan, which
is balanced by default. On the next screen, click "change advanced
power settings", look for "USB settings" in the list and put "Setting"
under "USB selective suspend setting" to "Disabled". This should
automatically deselect "Allow the computer to turn off this device to
save power" on all USB root hubs power management tab, but you can
check it manually in the device manager to be sure. The USB power
saving feature should now still be disabled after rebooting."
Thanks a lot for the help!