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CB Timing 1234

To perform a circuit breaker timing test: 1) Connections must be made from a circuit breaker analyzer to the input and output of each phase of the circuit breaker. 2) A DC supply must be connected to the tripping coil from an external source. 3) Connections are made as shown in the connection diagram, with the circuit breaker state noted before pressing the ready button to operate and time the breaker.

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Akshay Gatkal
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977 views1 page

CB Timing 1234

To perform a circuit breaker timing test: 1) Connections must be made from a circuit breaker analyzer to the input and output of each phase of the circuit breaker. 2) A DC supply must be connected to the tripping coil from an external source. 3) Connections are made as shown in the connection diagram, with the circuit breaker state noted before pressing the ready button to operate and time the breaker.

Uploaded by

Akshay Gatkal
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Circuit breaker timing test procedure and

Connections
To perform breaker timing test, following connections are required.

 Connection to the input & output of each phase of circuit breaker from circuit breaker analyzer.
 DC supply to the tripping coil of the circuit breaker from external source.
 Connection to the tripping circuit of breaker from CBA.
Following figure shows the typical connection diagram.

As it can be seen from the figure that connection to incoming of each phase of breaker is provided from CBA via
red, yellow and blue wires while outgoing is connected with black wire. Positive (+) and Negative (-) sign shows
the connection of external battery to the triggering circuit.

When the connections are done, note the state of the circuit breaker from breaker state indicator (on or off).
Press the ready button, the circuit breaker will be operated and the time will be displayed on the screen. Results
of the timing test of circuit breaker can be printed using thermal printer, downloaded directly to USB via USB port
and displayed on PC via USB interface. Repeat the process for closing and opening of circuit breaker.

Accepted Results
The exact correct operation time of circuit breaker is provided by the manufacturer. It can be mentioned on the
nameplate of circuit breaker. Click here to learn how to interpret name plate of circuit breaker.
However as a rule of thumb, operating time of circuit breaker should fall in the following ranges

HT breakers (above 11kV) Opening time = 1-2 cycles (20 – 40 ms)


Closing time = 2-5 cycle ( 40 to 100ms)

LT breakers (11kV or below) opening time = 2-3 cycles (40 to 60ms)

Closing time = 3-6 cycles (60 to 120ms)

These are just estimated values which can be regarded as acceptable operation time.

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