Member Login

Remember Me
Forgot Password?
Join Us!

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

Join Eng-Tips
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Jobs from Indeed

Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

application shunt trip for mccb

application shunt trip for mccb

hi all,

i want to know more specificly about how to install and operate shunt trip for mccb (low voltage cb). because so far, i only ever seen mccb operating by handle (manually).we use hand to rotate that mccb. and for ACB, i have known that ACB can operate by push the button to open/close the tripping coil.
my question is can we operate mccb automaticly like we do to ACB? may be use shunt trip?

thank you

RE: application shunt trip for mccb

Contact the manufacturer representative for you MCCB.  Many models have shunt trip devices that can be field-installed.  I have installed many myself.

We use quite a few of them for isolating equipment under emergency shut down conditions.

old field guy

RE: application shunt trip for mccb

Shunt trip is easy if the breaker is intended to accept field added accessories.  If not you'll have to buy breakers with shunt trip from the factory.  Check with the manufacturer of your breakers for more information.  You won't find a shunt close so you won't get the equivalent operation of an ACB.

RE: application shunt trip for mccb

A shunt trip coil only "trips" the MCCB when energized via external means but cannot close the breaker. MCCB do not have internal means to automatically close it like a close coil in an ACB. Not very popular but some cases you can use a motor operator which essentially operates the "handle" of an MCCB to close and open the breaker.  

RE: application shunt trip for mccb

Shunt trip is a method of opening the breaker only; it does not close it. Many MCCBs now come with "Push-to-Trip" buttons on the front of them that can open the breaker, but it is in the Tripped position afterwards, not the Open position, which is different as far as auxiliary contacts go.

Siemens offers an external accessory on their VL Series MCCBs which is essentially the same as the charged energy closing system on ACBs that can close the breaker remotely. It has a pull handle to charge the spring or it can be done with a small motor.

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln  
For the best use of Eng-Tips, please click here -> FAQ731-376: Forum Policies  

RE: application shunt trip for mccb

The motor actuators rbulsara mentioned typically have a spring close, motor open arrangement. This allows use for synchronising. The motorised opening still relies on the breaker mechanism to ensure rapid transition of the contacts, but the operation takes a couple of seconds to complete. For a rapid opening the shunt trip is the better solution. The two methods can be used on one breaker: tripping an MCCB is different to opening it.

If we learn from our mistakes I'm getting a great education!

Red Flag This Post

Please let us know here why the post below is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close