More Questions about Protective Relays

[Josh111]

I am trying to protect two power sources from two generators from overcurrent, under/overvoltage, under/overfrequency,etc.
There will be two generators running during the day and one running at night, I have double throw switches to switch the two breaker panels to run on one generator each or to share one generator. One generator's relay will run almost 24/7 and the other will cycle once per day.(Generators not ran in parallel.)

I do not wish to use a shunt trip breaker connected to the protective relays for this purpose because I do not have an uninterruptable power supply. I was thinking of using a normally open contactor instead. I know a regular electromechanical relay will not last long in this application. What I am wondering is if it would be best to use a solid state relay or a mercury relay or something else for this application?

The generators are 83 amp 120/208 volt 3 phase 24 KW.

 

[fleem]

Since safety is obviously an issue, and there are just so many unanswered questions about your setup, I wouldn't rely on guesses found in a forum. To make a good decision here, you need a pro electrical engineer that has intimate knowledge of your setup and requirements.

 

[Josh111]

This is a home project I am just looking for something that will last and not get weak if I used electromechanical contactors continues rating and hold contacts the problem would be the risk of the coils becoming weak and failing this is all I am asking about. If the contactor fails, there is no immediate danger. I am an electrician.