I sell & install home standby generators. While I've been asked to price big machines, I've never sold one. I do from time to time work on them. Something to be VERY careful about is confirming you buy a machine you can configure to meet your power needs. Most large ones can be reconnected to choose your power choice, a few can't. I've gone to look at former military generators to find they are only 208/120. Others are 50 cycle, usually a manageable change. Motors & other magnetic machines depend on "magnetic choke" to limit current. An across the line starter sends power to the motor. Magnetic field builds from 0% to 100%. At the instant it starts your magnetic field is zero. Starting current may be 700% to 1200% of running current. If it overloads the engine, it may slow the generator, lowering frequency, and voltage, as current spikes. A variety of failures can occur. Soft starters, or VFD controls can help. Be very sure your generator is big enough.