Contractor Coil Voltage

There are usually no extra controls in a system....what you want to ask yourself is what will change if I remove this part of the system...everything is usually there for a reason, unless the system has been modified in some way from its original design ...

Optimized for what; lowest or highest parts count, reliability, profit margin, flexibility, standardized parts, cooling, heating, accurate failure mode detection, other?

It is likely that the rating of the voltage sensing relay output is not robust enough to handle reliably the 24v trip coil current & especially interruption. The interposing relay also adds the possibility of remote monitoring of the equipment, as an option for the upgraded version of your equipment.

It’s general practice to have all trip circuits and protective circuits in 24 V, independent of source.

The existing system is best with out any interference from AC source.

In this case for any over voltage the contractor coil will not get damaged.

There seems to be a suggestion in this thread that it is not even legitimate to ask: Is there a simpler and more elegant method to achieve the same result? Opposition to the posing of this question is an odd attitude to find on an engineering forum - the attitude that this is the way it is done, the way it has always been done, and there is no better way to do it. The question of the original poster is specific to an electrical control circuit, but regardless of the field of endeavor, the question, taken in its generality, is the question that drives innovation. The majority of granted patents make no claim that they accomplish what has never been done before, but that they do exactly what has been done before, but in a simpler, more elegant manner.

<...the OV UV relay is powered From mains 415vac and then it is used to power a 230V aux relay. the contacts of this relay is wired to the 24vdc coil of the contactor Which will do the switching and power the AC...>

The simplest system would be to do away with all that rubbish altogether, and simply lob a suitably sized crowbar across the open-circuit conductive parts when an electric circuit is needed. That would work too.

What <...we...> does is regulated by the end Client's construction standards. The word <...we...> indicates there is more than one at that location. So why not discuss it among the rest of the <...we...> instead, and find out why it has been done that way, straight from the proverbial horse's mouth?

The forum knows nothing about the Client's standards, because the <...we...> has deliberately withheld this information from it.

Go figure.