Three Phase Generator Control

I have a 50kva generator to run some pumps in a yard.The pumps need turn on every 5 hours throughtout the day.I have a 230v Mains in the yard and i hope to use this to control the control circuitry to keep the timers up to date.I also need the supply to the pumps to lag at least 30 seconds behind the start up of the generator.A simple circiut to run this would be appreciated.