I need to defend some of my terse comments as it seems:
Originally Posted by C-5Crewdog
..However, the generators can produce power once the engine has reached idle speed. They do not need to spin faster than idle to provide power..
To be picky as you set the standard for: if you drain any power from them, they
need to be at a higher setting than for pure idle power. Admittedly most of
the drained torque goes to the fuel pumps if the generator drains power,
torque goes there are well.
As the engine is a dynamic, unconfined heat-power machine, the power-torque-
rpm-air flux are related monotonically (given steady state operation). So
more power requires more rpm. You may rename that 'new' minimum level as
idle level thoug that's a mere matter of taste. And yes they do not have to
be at cruise or takeoff setting to produce electrical power.
Having only one engine running at idle likely did not produce enough bleed air to sufficiently cool the cabin..
Bleed air is hot as it was previously compressed adiabatically by - well - the
compressor. So it is unsuitable to cool the cabin in the first place and has
to be fed through the airconditioning pack where it is cooled and expanded.