Simocode Overload Relay

We are using Pro -V, we changed the circuit from from DP to Pro-v, after changing the Prov keep on loosng memory

What module types [siemens part No.] are a) losing memory b) burning?

"Burning" - what parts are visually burnt? Resistors? Integrated circuits? PCB tracks or.... ??

Lightning strike or voltage spike/surge on supply could cause both memory loss & burning according to magnitude.

Do you mean that several events of memory loss occur on same card before "burn"??

If you keep on doing what you always did, you'll keep on getting what you always got.

You will need to trouble shoot the circuit to find the cause. The forum cannot do that for you.

Perhaps a call to the Simocode and Pro V folks would be a good start.

You are not help, i didnt ask u to do faultfinding for me

Sorry, I must have misunderstood you. I assumed that "what can be the problem? please assist," meant you wanted help.

Typically, the amount of help received is inverse to the number of snide remarks made by the requester.

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Thanks for your assistance Lyn, God bless you.

Losing the memory or burning the card could be two separate problems, or one, depending on what is burning.

If your communications card is burning, I would use your meter and test for voltage between your power system ground and your communications ground or common. Most electronic equipment cannot withstand large differences.

Also, the circumstances when & how you discover the failure are important, even if no apparent cause or event, that too is important to know.

Card burning - is it power supply card! If true, could be due to overvoltage at simocode input terminals!

We had problem of relay power supply card burning due to over voltage at relay auxiliary power supply terminals.

More information would be useful but perhaps you have not had the time to make certain observations. Frequently motors are connected together and fed from a large transformer. You must remember that motors and transformers consist of very large inductors which don't like to have their current interrupted. When a relay opens up and the current is interrupted it is possible for the voltage to rise to a point where an arc can occur between contacts. Too much of that will overheat the relay and associated contacts. Furthermore, too much of that can cause other damage to connected devices so it would be good to solve the problem right away.

One way to do this is to install one or more line reactors which are just inductors in series with the motor contactor. The reason that this works is that inductors become high impedance devices during high frequency events like a current interruption. The sudden increase in voltage is then split between the contacts of the relay and the line reactor. At normal frequencies (50 or 60 Hz) the impedance of the reactor is very small but they do get pretty warm. Consequently, you will need to figure out what to do with the heat. Generally most people mount the reactors in a separate box above the control cabinets so they don't heat up your cabinet.

Go to your favorite industrial supplier and search for "line reactors" and consider if this isn't a decent low cost fix for your problem. Let me know if you find any line reactors in your distribution system now. I doubt they were considered.