Self-extinguishing graph of a SF6 circuit breaker

Self-extinguishing graph of a SF6 circuit breaker: The Power System measurements were carried-out at 33kv primary bus, across a 150mva, 33kv/1120v, Electrical Arc Furnace Transformer, supplying to a 180 Ton EAF Furnace, connecting through a set of 2nos. 2000A, 33kv, in parallel, SF6 Circuit Breakers.

The captured waveform graph is the drooping characteristics of a 3phase system voltage and load currents, while switching off the 2nos, 2000A, 33kv, in parallel SF6 circuit breakers, of the EAF transformer.

Motor switching inrush current

Motor switching inrush current: The recorded Current Waveform view, as shown in the caption picture above for a few milliseconds, shows normal oscillations with the 3phae system voltage and motor currents of a motor starting with soft starter for a Tyre Industry's Banbury Mixture Motor of rating 400kw, 660v, 3ph, 50hz. The RMS snapshot view, as shown in the picture below lasting about 7seconds, shows that after the initial millisecond starting oscillations, both the system voltage and motor currents drooped back to their rated values, which depicts a normal motor starting characteristics.

Runaway power oscillation and core saturation

Runaway power oscillations and core saturation: A motor starting with soft starter of a Tyre Industry's Banbury Mixture Motor of rating 400kw, 660v, 3ph, 50hz. The recorded RMS graph view, lasting totally about 6secs, shows high oscillations at the starting instant with the 3phae system voltage and motor currents, which lasted for a longer time than the usual time of a few milliseconds. Thereafter the system voltage and motor currents did not droop back to their rated values, which happens with normal motor starting.