Emergency Instrument Power Switch

I haven't read the whole POH manual yet, but gradually take my time.

But I am going through the checklist and try some buttons and switches.

When I move the bar for the Emergency Instrument Power I get a sort of vacuum cleaner sound that stays on even if I turn the switch to its normal position.

Then I tried to disengage it by disconnecting battery and ground power but the sound keeps running.

Is that kind of normal behavior to expect when switching emergency instrument power ?

Just curious thats all, and keep digging into the systems....