Cutler Hammer DS II Breakers tripping
Cutler Hammer DS II Breakers tripping
(OP)
Has anyone had any issues with Cutler Hammer DSII breakers with RMS overloads tripping for no apparent reason? We have had numerous trips on these breakers at very low loads with no indication as to why they are tripping. Cutler Hammer has suggested that it is a humidity issue.





RE: Cutler Hammer DS II Breakers tripping
These trip units can failsafe to the lowest setting from failed compoents or dirt accumulation in the trip unit. We repair and replace these units every day.
www.cbsnuclear.com
RE: Cutler Hammer DS II Breakers tripping
I'd have the trip units tested ASAP - ALL of them.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
We can probally repair your failed units and do a more in depth analysis on what is causing the failures.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
Something does not sound right. Firstly, as requested eariler by others, you need to provide more details as to what those "screwy" results mean?. Who tests your breakers and when were they last tested? What type of loads are served? What are the ambient conditions etc. Provide set points.
It may be true that real harsh conditions may be damaging the electronics in the trip unit.
What I have understood from many experienced people is DSII breakers are some of the better made breakers in the united states. . You may want to speak to some different people at CH.
RE: Cutler Hammer DS II Breakers tripping
I'm not really buying the moisture explanation.
RE: Cutler Hammer DS II Breakers tripping
We also have GE micro versa trip plus, Siemens static trip, and ABB overloads. These overloads have never caused problems and are outdoors with non-manuf. switchgear.
CH salesman made a site visit as well as CH field service technician.
We are at the end of our rope. Of course, other than replacing these overloads with new ones.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
When you have less than 20-50% (Depending on type of trip unit) the CT's dont have enough output to power the trip unit so it runs on battery power, running at 15% load will cause the battery to go dead, if the battery is dead the trip unit will not display the cause of trip.
My guess is that the dirt/moisture has caused the trip units to fail to default settings, which would explain the trip before the expected trip value and dead batteries causing the lack of the unit displaying the cause of trip. However I am guessing my guess is wrong because I would expect a C-H tech to know this and have explained this to you already.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
You got me curious on this one, I would be willing to have our lab evaluate one for you if you like.
RE: Cutler Hammer DS II Breakers tripping
Nothing in your posts suggest that any more attempt than just the secondary injection test by others have been investigated. Why not primary injection test? It does appear that the trip units are damaged. They key is to find out exact cause.
I would try to arrange sending one or two bad breakers to CH factory and have them diagnose the exact cause. With their reputation on line they will be happy to do that.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
FWIW, I agree with Zogzog and I would not simply accept this explanation. These "overloads" are digital computers. Does C-H have an explanation of exactly how moisture is causing these to initiate a false trip?
What are the environmental specifications for these trip units? Generally, as long as the ambient air is non-condensing, it should not be a problem.
If the moisture is that severe, you should be seeing numerous other problems with other electrical equipment.
If you have to buy replacements, I'd sure get something other than another C-H unit.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping
Any update on your C-H breakers? We have four C-H breakers that have had mysterious trips as well. They are DSII with Digitrip 510. We have other similar breakers on site but only these 4 have had the problem. With each trip there are no lights on the trip unit (batteries are good). However, the OTS operates to indicate that the trip unit has tripped the breaker. We are replacing trip units to address the immediate issue but so far we do not have a root cause.
RE: Cutler Hammer DS II Breakers tripping
RE: Cutler Hammer DS II Breakers tripping