To begin with, we will designate a problem with which in this article I will fight.
Many voltage relay models have built-in thermal protection. It is intended primarily to protect its own input contacts from overheating.
The action of this protection is manifested as follows: The voltage relay disconnects the power contact, we lose voltage, and 3 squares are lit or flashing on the screen. Thus, the relay is trying to tell us the reason for the shutdown.
According to the instructions, we must either reduce the load or tighten the input contacts on the relay itself. But!!!
The contacts are crimped, and the load is insignificant (less than 1 kW) .... however, the relay continues to operate, displaying squares on the screen.
So what is he missing?
At the end of the article - a video version of the repair of this voltage relay on my YouTube channel.
We remove the relay from the DIN rail and disassemble it by unscrewing 4 bolts:
The first thing you need to pay attention to is the bolted connection indicated by the arrow in the photo below. If it hangs - that's the first reason for you!
If everything is normal, unscrew the board from the bottom of the case.
And here the most interesting begins.
If the power bus is connected to the relay not as in the photo above, but to the board ... by soldering - here is the second most likely reason for you.
A few years ago, one of my acquaintances, an electronics engineer, pointed out to me this "disease" of almost all voltage relays. There is only one way out - to solder all the relay contacts on the board. Somewhere there may be a microcrack, "cold soldering" ...
With a similar soldering, I brought back to life several relays with symptoms of unreasonable operation of thermal protection.
In the case considered below, the power contacts come straight to the relay (top). However, you also need to solder the contacts on the board. Also, it will not be superfluous to solder the diodes. All places that you should pay attention to are circled in yellow:
Hope this simple tip helps you someday. And now, the promised link to the video: https://youtu.be/YwzYt31wKaI