Microprocessor controlers in circuit breakers

[cranky108]

Has anyone else come across newer circuit breakers with microprocessor controlers? The problem I am running into is the trip circuit the manufacturer is expecting me to use is different than the IEEE PRSC paper on trip circuit design. The problem is the trip current is less than 20 mA, and the trip voltage is about 18 volts. This means it is incompatable with the red led position indicator on the panel board.

When I asked the breaker manufacturer about this, they said that we don't need to monitor the trip circuit, because the microprocessor monitors the trip coil. It seems we are losing something here, and it isen't a great benifit for the utility.

 

[dpc]

Assume you are talking about medium-voltage breakers? I'm not really fond of the new ABB R-Mag breaker mechanism, but I haven't seen the problem you are describing. I don't see that an interface like that would meet ANSI C37.

 

[ScottyUK]

ABB's LV breakers have a similar problem - the trip coils are either very sensitive and needs very little current to operate it, or has some kind of semiconductor circuit internally. Either way the standard TCS circuits won't work and you are forced to use their 'SOR' relay instead. Irritating to say the least - this and a separate QA/QC problem last year have really changed my impression of ABB's LV / MV switchgear for the worse. The big gas-insulated stuff out of Switzerland is still excellent.

 

[cranky108]

I was thinking more about this in the shower this morning, and this seems simular to the problems we (I worked for a different company then) had with the ESV. Except then the interface was an ice cube relay. Which started me wondering if this is the same division of ABB.

My purpose in this post was to see if we really were the only ones with this problem. ABB clames that we are.

 

[dpc]

Well, it didn't take us long to figure out the manufacturer, if that tells you anything. We've had some strangeness in the ABB breakers when racking in and trying to get them to function. This is in metal-clad gear and seems more related to the racking mechanism, limit switches and the socket/plug arrangement for the control wiring.

But ABB isn't alone with having problems with metal-clad switchgear around here.

 

[vandal06]

I can't offer much detail since I didn't have a heavy hand in it, but I do know several of my colleagues have grumbled about newer MV ABB metal-clad switchgear breakers we've used on projects, specifically problems with interfacing the trip coil monitors with protective relays. So if ABB says you are the only client to have issues with these breakers that sounds like BS to me.

 

[ScottyUK]

I wish we had used Siemens components.

 

[Zogzog]

THey don't make em' like they used to.