CircuitBreaker

[Engcan]

Hi
I got a catalouge from G&W electric but the guy who gave me was a sales guy. I have just started as an engineer.
The catalouge talks about this switch in this link below:

http://www.gwelec.com/pdfs/app_guides/appguide5.pdf

Should I assume these days, Switches is the term that is being used for circuit breaker.
These terms have been used :
1. Padmount Vacuum Interrupters
2. Vault Vacuum Interrupters

Is 1 & 2 both circuit breaker and will be only activated by a relay operation that means these are circuit breakers. Plz advise so that I can get out of this confusion.
One last thing, when It comes to choice of SF6 and Vacuuum what are the considerations we take in to consideration.

Thanks

 

[Engcan]

Hi Guys,
I beleive it is not a difficult question, yeah might be stupid one...... Would appreciate reply.

Thanks

 

[supraskate13]

OK circuit breakers are mechanical devices that break a circuit...the "Interupter" is a component of the circuit breaker that helps to extinguish the arc. The "Vaccum Interupters" are simply vaccum bottles that the contacts of the breaker are incased in, when the breaker opens...the vaccum provides no median for the electrical current to pass through and there for the Arc is "interuppted"

SF6 provides a better insulation then air and there for can break an ARC with a smaller gap than required with AIR. the major difference in using SF6 and Vaccum is SIZE required. Usually SF6 Breakers are bigger then Vaccum Breakers. Typically you will not find SF6 breakers smaller then 34.5 kv although they my exist.

More testing is involved with Vaccum Interupters as well. As you need to do a Megger Test and A Vaccum Integrety (HI-POT) test along with the other normal tests that me be required of the breaker.

I know this may not answer all the questions but I hope it helps

 

[rbulsara]

Lets get the basics right.

Both pictures are of a manual "Switches", also called "interrupters". One on the left is oil filled (insulated) switch other has vaccum bottles enclosing the switch contacts. These are NOT circuit breakers.

Circuit breaker is device that is equippled with sensors and mechanism to OPEN "automatically" upon sensing of overcurrent conditions. Circuit breakers are normally manually closed, but can be designed to close electrically from a local or remote switch/pushbutton.

As for selecting between SF6 and vaccum intrrupeters you need to read up more from manufacturer's websites. Also if you describe more details of your application, like what your are switching, voltages, ampere rating etc..someone may help you more.

I hope that you are workig with some experiences engineer on this project.

 

[wbd]

From the dwgs on the link, the symbol for a circuit breaker is shown. There is also a electronic control box which contains the trip sensor, which can be set to emulate various devices, ie fuse, CO relay, IAC relay etc. The switch will trip on overcurrent and then will have to be reset manually, so it does function like a circuit breaker.

 

[stevenal]

I'm afraid I cannot find the word switch anywhere in the linked document. The thing on the left is a fuse cutout. IEEE C37.100 is a good reference for the various terms. There is some overlap in function, though. By calling it an interrupter rather than circuit breaker the manufacturer is in effect choosing which standards apply and which don't apply to the product. An interrupter probably needs no standard reclosing duty for example. See the standards for details.

 

[rbulsara]

In the drawing attached in the link, please read the title on the box where the "circuit breaker" symbol is drawn. It says Switch. Read all the notes below it, it mentions nothing but the switch.

In fact there is no mention of a circuit breaker. But interrupter and swith is written all over it.

Regardless, none of them is a circuit breaker.

 

[rbulsara]

I am not sure what the electronic controller does..it may be a shut trip type arrangement. I would please ignorance to that, but even that won't make it a circuit breaker in a conventional sense.

As for the oil filled cutout goes, the linkage connecting all three allows disconnceting all three phases inside, (I beleive) it may have fues links too. Calling up G&W won't hurt.

 

[stevenal]

Now I see it. I agree that it is not a CB, for the reason I gave above. I believe the symbology is okay though. Until someone devises separate symbols for fault interrupters, reclosers, circuit switchers, etc.; the CB symbol is the closest one to indicate the function.

 

[dpmac]

Note 6 on the drawing states:

Switch is equipped with 500:1 current transformers.

 

[cuky2000]

This product may be classified closer to a circuit switcher rather than a circuit breaker because do not have reclosing duty cycle rating.

This protective device is rated through 35kV, 630A continuous and 12-18 kA symmetrical short circuit consisting of a combination of a loadbreak switch with operator handle and vacuum interrupter bottle tripped by electronic control module with selectable TCC powered by CT’s mounted inside the SF6 deadfront enclosure.

 

[matwong]

It is a bit confusing when lack of information (as we only refer to the drawing).

Once we get into the other site, i.e "

http://www.gwelec.com/product_vault/vault_vi.cfm"

then we just realise the manufacturer actually meant vacuum interrupter for circuit breaker which say "The vacuum interrupter trip module monitors the current .... activates a trip ..... opens the vacuum interrupter......". It can be called CB because it can function Break the Circuit in this case. Moreover, CB can be originated from switches but adding some kind of control & monitoring features.

Also, the application is for replacing a fuse-cutout. Switches should not be used for it doesn't have protection feature.

On the other aspect of the query, if I understand correctly,
a) padmounted XX refers to the equipment installed on the ground, i.e with support structure/frame.
b) vault-mounted XX refers to equipment to be mounted on the wall.
XX can be anything like recloser, switchgear etc.