Reliability Issues

[Jed057]

Hi,

there have been frequent trips in our factory, we will have a meeting with our electrical specialists involved in reliability.

What topic we should review to improve reliability ?


young engineer

 

[gar]

100422-0844 EST

Put some monitoring equipment on the circuits to see what type of signal occurs and timing. Monitor voltage and current of each phase, and neutral, and maybe the EGC.

The design of your system will really define what you need to monitor. I would suggest you want 1 second sampling plus some instantaneous information. The 1 second sample rate will produce large files of data.

You can not reasonably store relatively instantaneous data for very long and therefore this monitoring should have some thresholding limits to control when data is saved.

.

 

[zog]

Hi,

there have been frequent trips in our factory, we will have a meeting with our electrical specialists involved in reliability.

What topic we should review to improve reliability ?


young engineer

When is the last time a coordination study was performed? That should be the first thing you look at.

When is the last time your breakers were tested? A common failure of breakers with electronic trip units is for them to fail to the defaults, which is usually the minimum settings.

 

[xformer]

would check the trip settings on your service breakers. Also, monitor the amperage on the GEC.. Worked in a plant one time that had 8 amps flowing on the grounding system that caused the mains to trip occasionally.. .

 

[mcclary's electrical]

would check the trip settings on your service breakers. Also, monitor the amperage on the GEC.. Worked in a plant one time that had 8 amps flowing on the grounding system that caused the mains to trip occasionally.. .

Could you further explain this scenario?

 

[xformer]

Could you further explain this scenario?

Sure..... Someone at the plant wired a panel the wrong way.. Caused a

ground loop in the system which resulted in 8 amps flowing on the GEC. When

you put an amp clamp on the green wire, it read 8 amps... The miss-wiring

caused just enough current to be shunted to Ground that the GFCi protected

Main breaker would occasionally trip..

 

[zog]

would check the trip settings on your service breakers..

Check them for what?

 

[Ken9876]

Check them for what?

To see if the settings are maxed out of course

 

[dbchamblee]

Check for harmonics, particularly on the circuits that have tripped. High levels of harmonic current can cause false trips.