Friday, March 4, 2016
MCB TEST CONNECTION
PROCEDURE:-
• Draw the above circuit on sverker.
• Make tight connection of above circuit, mcb and check properly.
• Press button SEL/Auntil you get a red light at the built in severker as per above diagram.
• Adjust sverker’s on AC from mode selection.
• Join the positive and negative wire and hold till set the 2times rating current as shown on mcb example( if the mcb In= 6amp then we set the double approximately 12)
• After setting current we push the “ON+Time” button to start injecting.
• Select hold button to freeze the current reading.
• Make MCB at “ON” position and check the trip time of mcb by adjusting and maintaining the adjustable main knob because we have to maintain the double current according to the mcb and check the drop off time as per factory report.
• Tripping time was shown on severker screen when mcb trip off
• We have to write down the mcb trip time and fill in the format.
• Why we do mcb test? The answer is if mcb was not trip in the limited time according to the factory report then it will become a cause of big damage such as internal short circuit, etc.
• In mcb there was two type of tripping; 1- thermal tripping, 2- instantaneous tripping.
• Thermal tripping occurs due to over current. This process is slow when over current was pass out through mcb; internally the bi metallic strips starting bends due to heat up and it will releases the latches which was connected to the spring.
• Instantaneous tripping also occurs from over current but this process was done very instantaneously 10 times faster than thermal tripping. When over current passed in a huge quantity then it will trip instantaneous.
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