Skip to main content

Basic Information on Circuit Breaker Maintenance

Circuit Breaker Test Set by KEP

Circuit Breaker Tester

Billions of circuit breakers are installed in residential and non-residential buildings, or are used for industrial applications. These automatic electrical switches make it possible to switch currents on and off during the normal operation of the grid, and to automatically switch the current off if it exceeds the permissible value for a certain period of time.

In order to allow for typical appliance-inrush-currents, the circuit breaker must remain stable during a minor short-term overload. However, if the overload persists, the circuit breaker must open the circuit after a certain period of time. During a short-circuit, a circuit breaker must interrupt the current safely in order to minimize damage.

Design and operating principles of a circuit breaker

A circuit breaker has a rather sophisticated design, consisting of two separate tripping mechanisms for overloads and short circuits. Circuit breaker tripping characteristics show a thermal trigger for overloads, and a magnetic trigger for short-circuits.

Inside of a circuit breaker, the path the current is taking across the closed contacts is visible, as are the tripping components. The higher the amplitude of the overcurrent, the faster a circuit breaker must trip.

This is achieved with a metallic element consisting of two different metals which are heated up by the current flow. The two metals are expanding at different rates while they are heating up. An overcurrent that is present long enough will eventually activate the breaking element. This mechanism is tripped when the current exceeds its rated value by a relatively low figure of 1.45 – 2 times. At the same time, the tripping time, which depends on the current value (the higher the current, the faster the heating time for the metallic element), can reach up to 2 hours.

A circuit breaker must open a circuit instantaneously when it encounters a short circuit at several times the nominal current. A solenoid and a piston are the elements used for instantaneous tripping. A short circuit creates an instant magnetic field that moves the piston and operates the breaker.

Another important point is that interrupting high fault currents can result in heavy arcing. Due to magnetic forces, the arc moves through a stack of metal plates, where it is cooled, split, and finally extinguished at the next zero crossing.

Testing circuit breakers

The quality of the materials used by the manufacturers differ widely.
Therefore, it is a good idea for users to test their circuit breakers and not simply rely on them.

During testing, the circuit breaker is disconnected from the circuit and connected to a primary injection test set, which, in essence, generates different currents in order to simulate load conditions and fault currents.

Circuit Breaker Test System

Circuit Breaker Tester UPA-16

In thermal-magnetic circuit breakers both the electromagnetic and thermal tripping elements need to be tested. The testing current is selected based on the technical parameters of the given circuit breaker provided in the respective documentation. These parameters stipulate at what current load and in what time the circuit breaker should trip.

As for the testing sequence, the short circuit tripping element is tested first. Then, the overload tripping element is tested, followed with a stability test with nominal current.
If either of the tripping elements fails to trip the circuit breaker in the set amount of time, the circuit breaker under test is considered to be out of order and must not be operated any longer.

Circuit breaker testers UPA-series by KEP

Circuit breaker testers UPA are intended for automatic testing of circuit breakers with alternating current. The devices allow measuring the values of the supplied current and timing the circuit breaker tripping time. The UPA operates on the principle of varying the power in the primary circuit of the matching power transformer and, respectively, varying the output current flowing through the circuit breaker under test.
Power adjustment can be done either through an external voltage source or through a built-in thyristor controller.

Alexei Tiatiushkin
Marketing manager
KharkovEnergoPribor Ltd.
marketing@keppowertesting.uk
http://www.kep.ua


http://news.chivindo.com/361/basic-information-on-circuit-breaker-maintenance.html

Comments

Post a Comment

Popular posts from this blog

BT-BASIC commands used

8.10     Some of the most frequently used BT-BASIC commands used are: msi                               Changes default working directory. Mass storage is            Same as “msi” cat                               Catalogs (list)the node names in the specified directory.             get                               Brings the contents of a file into the system workspace.        ...
1 comment
Read more

Perhitungan & Cara Merubah Kumparan Blender Dari 220 V Menjadi 12 V

          Seperti yang telah dijelaskan pada buku “menggulung motor listrik arus bolak-balik, servis peralatan listrik rumah tangga kelompok penggerak dan perbaikan peralatan listrik pertukangan”, bahwa motor penggerak yang digunakan pada perlatan listrik rumah tangga dan pertukangan seperti blender, mixer, bor tembak, gerinda dsb menggunakan jenis motor universal. Motor universal adalah jenis motor listrik yang dapat disuplai dengan sumber listrik arus bolak-balik (AC) dan arus searah (DC). Jadi peralatan-peralatan listrik rumah tangga dan pertukangan tersebut yang biasanya kita suplai dengan sumber listrik AC dari PLN atau Genset sebesar 220 V sebenarnya dapat juga kita suplai dengan sumber listrik DC yang tentunya tegangan juga harus sama yakni 220 V.           Yang menjadi permasalahan bagaimana kalau peralatan listrik rumah tangga atau pertukangan tersebut, sebagai contoh misalkan blender yang ingin digunakan atau dioper...
1 comment
Read more

BT-BASIC command line

8.8       At the BT-BASIC command line type the command  msi  and the directory path, then press the “ENTER” key on the keyboard.  Example:                   msi ‘/hp3070/boards/aspect/main’ 8.9       At the BT-BASIC command line type the command  get ‘testplan’ and press the   ENTER” key on the keyboard.  You should now see the body of the testplan file displayed in the work space of the BT-BASIC window. 8.10     Some of the most frequently used BT-BASIC commands used are:
Post a Comment
Read more

Autodesk SketchBook Pro 2021 Full Version

BAGAS31 – Sesuai dengan namanya, Autodesk SketchBook Pro 2021 Full Version ini merupakan software digital sketching atau drawing terbaik yang bisa kamu gunakan. Pada versi terbaru kali ini, ada beberapa penambahan fitur yang sangat efektif. Dengan fitur baru tersebut, diharapkan mampu meningkatkan proses sketching maupun drawing kamu. Autodesk SketchBook sendiri sudah bisa kamu dapatkan secara gratis melalui website resminya. Namun untuk kamu yang mau download versi Autodesk Sketchbook Pro, maka bisa langsung download melalui link yang sudah saya sediakan di bawah ini. Download Autodesk SketchBook Pro 2021 Full Version Screenshot: System Requirements: Windows 10 2.5 – 2.9 GHz of Intel or AMD CPU 4 GB of Memory 256 MB Graphics card with OpenGL 2.0 support We recommend that you use a pressure-sensitive tablet and pen for basic features Download: Autodesk SketchBook Pro 2021 Full Version [ FileUp ][ Uptobox ][ UsersDrive ] Jamu Only [ File...
2 comments
Read more

Testhead

4.3         Testhead The testhead is that portion of the tester that supports the PIN, ASRU and Controller cards.   The testhead is divided into two BANKS and each BANK is divided into two MODULES, see figure 2 below.  Bank 1 contains modules 0 and 1, bank 2 contains modules 2 and 3.  The test fixtures are placed on the banks of the tester and locked down for board testing.  The testhead cards interface to the test fixture through the spring loaded pogo pin “nails” at the top edge on each of these card types. 4.4       Support Bay The support bay is a stand-alone cabinet that houses the power supplies for the Unit Under Test.  This bay also houses the test station power distribution unit and test station controller on earlier models. 4.5       Emergency Shutdown Switch The emergency shutdown switch is the large red button located at the lower left corne...
Post a Comment
Read more

Kelebihan dan Kekurangan Saluran Listrik Jenis Saluran Udara dan Saluran Bawah Tanah

Berdasarkan pemasangannya,   saluran distribusi dibagi menjadi dua kategori, yaitu : saluran udara (overhead line) merupakan sistem penyaluran tenaga listrik melalui kawat penghantar yang ditompang pada tiang listrik. Sedangkan saluran bawah tanah (underground cable) merupakan sistem penyaluran tenaga listrik melalui kabel-kabel yang ditanamkan di dalam tanah. 1.    Saluran Bawah Tanah (Underground Lines) Saluran distribusi yang menyalurkan energi listrik melalui kabel yang ditanam didalam tanah. Kategori saluran distribusi seperti ini adalah yang favorite untuk pemasangan di dalam kota, karena berada didalam tanah, maka tidak mengganggu keindahan kota dan juga tidak mudah terjadi gangguan akibat kondisi cuaca atau kondisi alam. Namun juga memilik kekurangan, yaitu mahalnya biaya investasi dan sulitnya menentukan titik gangguan dan perbaikannya. Kedua cara penyaluran memiliki keuntungan dan kerugian masing-masing. Keuntungan yang dapat diperoleh dari suatu jaringan bawah...
Post a Comment
Read more