Dual CDVRs

I am not aware of any cat gen requiring 2 voltage regulators...What is the model? Is it possible it's a mistake? Do you have 2 existing in the panel now? What is the application?

Application is normal, it is just a standby backup gen with utility as prime. Small 350kw gen. Customer just wants to have redundant CDVR on one gen. If one faults for the other one to pick it the field, and continue to regulate.

Honestly I think it is not needed. Its not like CDVR break every week.

Redundancy is a fairly common requirement.

As OP alluded to, voltage regulators don't fail that often and I'll add that there a lots of other system elements that are more likely to fail and yet they are not redundant.

In critical power situations it is normal to have 2 backup generators in addition to mains supply. This provides full system redundancy regardless of which element fails. Also provides cover during periodic maintenance (eg oil change et al) or repair unavailability of one standby unit.

The Dual VR seems like a feeble attempt at providing some redundancy on the cheep.

If this is a Caterpillar sanctioned option then maybe they know something about the MTBF of their VRs that they don't want to openly declare.

Simple switching would be complex but it would work. Simplest manifestation would be unplug old and plug in new....

If they are designed to work in an automatic 1+1 configuration then it will be documented somewhere. Sorry I can't direct you to any.

Have you attempted to contact your friendly local Caterpillar agent yet?

If your client is super paranoid then suggest that they install 2 standby generators and a 3-way ATS. Get the economy moving.