Experimental investigations of internal pressure in quenching chamber of low voltage MCCB

For a kind of commercial MCCB, arc current, arc voltage, internal pressure of arc extinguish chamber, and arc moving images under different breaking conditions have been measured respectively, based on ATiS BE12 data acquisition system, pressure sensors and high-speed camera. Based on Kistler sensor and electromagnetic screen cover, an arc extinguish chamber internal pressure measuring method has been established. Meanwhile, the influence of arc power, gassing material and outlet cover plate on pressure has been investigated. Experimental results show that the pressure waveform almost has a consistent trend with the arc power. The internal pressure has been improved apparently because of the presence of gassing material. The peak and rise rate of the pressure will be higher when there is a outlet cover plate and the pressure peak slightly ahead of the arc power peak.