kybaseball wrote "I have a 7500 watt generator that I will be using. I plan in putting in a 10 circuit transfer switch. My bother in law thought the generator wouldn't be enough to run the air handler."
I just installed 8500 watt / 10,000 watt for my son a few days before Christmas. He wanted to try the heat pump with nothing else running and it wouldn't start. Tripped the breaker on the generator. He also has an oil furnace and it uses the same fan as the heat pump for the duct work and it ran that with no problem and hot water heater and well all on at the same time but started at different times. This spring we will try the air conditioner from the heat pump but will delay the fan from starting till the air conditioner is fully started and then start the fan. I think that will work. Just need to get each motor running one at a time before starting another and be reasonable with how much you can run at the same time. Only other option is to buy a larger generator. He's happy with what he has if we can get the air conditioning working and if that works out the heat pump may run as well with the delay for the fan. I'll use a timer to start the fan.
Your first post about the variable fan had me thinking why a generator wouldn't work because input power would be the same. I see no reason for any problem there. The Allen-Bradley VFD's don't care where the input power comes from as long as it's the proper voltage.
I have a PTO generator 13,000 watt running and supply my whole house but I have no heat pump or hot water heater. I use a plate exchanger from the Central Boiler for hot water. My blower for heat is 3/4 hp, have refrigerator, chest freezer, washer/dryer and electric range and small microwave. I use led lights all over the house, 2 computers and 2 Tv's. Generator has no problem pulling it all or any combination without a grunt from the tractor. On the tractor I shift to 1000 rpm pto and run the 540 rpm pto generator. Engine runs at 1,200 rpm instead of 2,100 rpm on 540. Engine is 96 hp and has fuel management and only burns what is required for the load. Burns about a gall per hour. Can run 38 hours on a 40 gal. fuel tank. I don't let the tank go empty and always refuel at 38 hours or before.
To test the generator while in use I use a Fkuke meter to check voltage and HZ and a hand held amp clamp for amps. The generator is brushless and is regulated. But I still check each time I use it to be on the safe side.
I don't use a transfer switch but use a mechanical interlock on the breaker panel. Less expensive and simple to operate.