Hi.
Bill, good trip to you.
Vitzwaters. Welcome to the club.
Small additionals,it's some expand of Bill's.
Please pay attention.
1. If you have voltages U and G, both of relays are closed.
It's wrong situation.
That mens you must cross with NC closed contacts K1(NC) in series with K2 coil, K2(NC) in series with K1 coil.
In practical with some type of breakers used mechanikal interlock. Don't remeber now, but I think mechnical interloccks is used for the contactors too.
BTW, smart relay, what LionelHutz mentonied is best practic today.
2. What is a L4/L3 S1/S2/S4, etc.
3. Next point, you need start from somewthing, that means
you need start and stop pushbuttons for every contactor, but of course via cross NC contacts.
4. Now, next options, your customer would like two options:
4.1. manual control only,
4.2. auotomatic changeover between main and genset source.
You need some rotated switch with 3-position manual-off-auto.
5. Please pay attention push buttons will feeded from suitble control voltages. PB;s of K1 from U voltages, PB's
of K2 from G voltages.
Nice start of design with EPLAN SW according IEC standards.
Good Luck.
Best Regards.
Slava.
Bill, sorry for my small remarks