Distribution panel tripping during power failure 4

[romanskat]

Hi Mates, need your advice on this:-

I'm now having Distribution board with sensitive load(old machines). When the recovery of up-stream power supply after black out, the incoming breaker of the Distribution board is still on and the surge always damaged our machines.

In order to avoid this senario, we trying to figure out a way to trip the incoming breaker of the distribution board when the up-stream power supply failure/ black out. So that when the supply recover, the breaker will remain "off" until our technician energize the board manually.

Any kind of solution available for me to source?

Thanks.

 

[waross]

Install an undervoltage release option on the breaker. The undervoltage will trip the breaker on loss of power and it will not be possible to reset the breaker until power has been restored.
respectfully.

 

[romanskat]

Thanks Waross!

Further more, do i required any backup power source like UPS in order to switch off the breaker when power failure?

Kind of confused of how it operation looks like.

Thanks again.

 

[RalphChristie]

What kind of breaker are we talking about?
Depending on the type of breaker, an undervoltage coil might/might not work. Most of the times (with an undervoltage coil internal to the breaker) you do not need any back-up power to trip the breaker. But if the undervoltage funtion will be used to drive a shunt tripcoil, you should have some kind of back-up, like batteries, capacitors, etc.

Regards
Ralph

[red]Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon[/red]

Make the best use of Eng-Tips.com
Read the Site Policies at FAQ731-376

 

[matrixabc]

The Under voltage coil should be fed from the upstream supply, it needs to be energized to allow a "shunt close" if there is no power the coil will de-energize and trip the breaker open.

 

[romanskat]

The application i'm facing is on a 100A MCCB.

Could educate me more on how to figure out the undervoltage coil is an internal type or shunt trip coil type?

Thanks.

 

[waross]

The smaller under voltage trips are a solenoid that activates the breaker toggle when it is de-energised. It must be energised to allow the breaker trip toggle to move to the normal position for closing.
Larger units are energised to operate and need either batteries or capacitors to trip the breaker.
All of them are braeker specific. Contact the breaker manufacturer to determine if under voltage trips are available for your breakers.
respectfully

 

[rcw retired EE]

A 100 A molded case circuit breaker would use an internal undervoltage release coil. You will need to order a new breaker with the UV feature. Some breakers can be field retro-fitted. Usually the waranty is voided if you break open the breaker case, so buying a new one is the recommended action. A good electrician could install the new breaker and the required fuse block to protect the coil. The coil leads will be connected to the incoming power wires and will have no protection unless a fuse is installed.

 

[romanskat]

Thanks Wilson , however how about the UV coil which is placed within the breaker? is impossible to have a fuse protection right?

Any brand to be recommended for my application?

 

[rcw retired EE]

Romanskat- The UV coils I have seen are mounted inside the breaker with two terminals or 18-inch pigtail wires out the side of the breaker. Those wires would connect to a small fuse block (rated for the short circuit current at the main) and the fuse block would be wired to the breaker's incoming lugs. I don't recall seeing a UV coil with an internal connection to the line lugs.

GE, Cutler Hammer, Square D, Siemens, and others all make good circuit breakers. Find out what type of breaker you have in the existing panel and try to match it. That will make the warranty and installation simpler.