This unit looks like it would be a fun thing to tinker with..
Equipment Description
The power management system is designed to control
six priority loads and up to two air conditioner loads that
are being supplied by power from the home standby
system.This power management system goes into a
STANDBY mode and does not control any loads when
utility power is present.
The power management system consists of a relay board
with 6 relays to control loads rated up to 120 VAC,
20 Amps, 1 hp, and a control module that has 2 relays for
central air conditioner loads.The circuit boards are housed
in a NEMA 3R enclosure that is suitable for both indoor
and outdoor installations.
Two (2) current transformers monitor generator current at
the transfer switch to ensure that the loading of the
generator does not exceed 85 percent. Should load exceed
85 percent, the power management system will start to
shed loads to keep the generator from overloading.The
power management system will add load back once
sufficient current is available.
The controle module has a green LED for each relay to
indicate when the relays are supplying power to the loads
when on generator power.There is also a status LED that
flashes when the power management system is functioning
properly.
http://www.homegeneratorsystems.com/pdf/owners_manuals/071013_0efsBw.pdf