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application shunt trip for mccb

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.

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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.

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