simocode pro v device 46 settings

[tonyjony]

Hi everyone, we are designing a water treatment plant. There are several pumps and compressors. The client wants to use Siemens simocode Pro V relays, but I don't know the range avaible to set the unbalanced load relay (% of unbalance or delay), niether the setting I should use. I surf all over the Siemens website, and nothing.

Thanks in advance

 

[jraef]

Well, you set it for what you want to protect against and what kind of tolerance you have for nuisance tripping. For example, if you want the BEST protection for a motor, set it for 5% imbalance; but be prepared for a LOT of resetting to take place, because 5% current imbalance is something that occurs quite often. I tend to set it for 30% (remember, this is CURRENT imbalance, not Voltage imbalance). But even then, I have had issues with nuisance tripping in areas with a lot of 1 phase residential services nearby, because the random nature of who's home with the AC running wrecks havoc on the utility's ability to maintain a decent voltage balance, so running motors tend to get a high current imbalance. As to the delay time, set that for an amount exceeding your acceleration time, because that can cause nuisance tripping as well. I actually set mine for 5 minutes if I have the tolerance set at 30% because most motors can handle the added heating of running at 30% current imbalance for that long.

The best thing to do however is to discuss it with the motor suppliers. What you will find on the web will all be in reference to Voltage imbalance, with a mention that the current imbalance is an exponent of the voltage imbalance percentage. But the motor mfrs can relate the heating effect of a current imbalance to the thermal damage curve of the motor.


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