METHOD FOR TRAINING OF CONTACT GAP FOR VACUUM CIRCUIT BREAKERS BY HIGH VOLTAGE Russian patent published in 2014 - IPC H01H33/664 H01H11/00 

FIELD: electricity.

SUBSTANCE: training method is implemented by direct-current high voltage feeding to complete gap between contacts in stages starting from 0.3-0.5 of rated operating voltage. Simultaneously permanent magnet field is created along direction of the gap and its intensity value is increased smoothly from zero up to prebreakdown current moment of about 0.6-0.8 of breakdown current at test voltage. The gap is hold at set voltage equal to 2-3 times of prebreakdown current measured at the beginning till drop, at the first training stage. Magnet field intensity is decreased up to zero and the next stage of training voltage is set. Value of field intensity is increased again from zero up to prebreakdown current available at the first stage. The above cycle is repeated at the next stages. At the last stage training voltage is set as 1.2-1.5 times bigger than testing voltage. The process is repeated at reverse polarity of high voltage applied to the gap and reverse direction of permanent magnet field.

EFFECT: reducing overspray of contact materials and improving electrical strength and reliability at decrease of power consumption.

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