Sammendrag
In this paper, an experimental investigation of the thermal interruption
performance of free-burning nitrogen arcs at 1 bar, 20 bar, and 40 bar filling
pressures is reported. This work contributes to the fundamental understanding of
arc characteristics at very high gas filling pressures. A resonant circuit is used to
generate an arc peak current of 130 A at a frequency of 190 Hz. An ignition
copper wire initiates the arc between a 4 mm diameter pin electrode and a ring
electrode. The arc burns freely at a fixed inter-electrode gap of 50 mm without
any forced gas flow. A resistive-capacitive branch parallel to the arc controls the
initial rate of rise of recovery voltage. By changing the parallel resistance, the
rate of rise of recovery voltage is varied from 9.8 V/μs to 84.8 V/μs. Time to reignition
and the corresponding re-ignition voltages are considered as the primary
parameters to characterize the thermal interruption performance. It is observed
that the re-ignition time rises with the decrease of rate of rise of recovery voltage
at all pressure levels, which is expected. However, in the absence of a forced gas
flow, high gas filling pressure results in a reduction of the time to re-ignition and
the re-ignition voltage in contrast to atmospheric pressure nitrogen arc.
performance of free-burning nitrogen arcs at 1 bar, 20 bar, and 40 bar filling
pressures is reported. This work contributes to the fundamental understanding of
arc characteristics at very high gas filling pressures. A resonant circuit is used to
generate an arc peak current of 130 A at a frequency of 190 Hz. An ignition
copper wire initiates the arc between a 4 mm diameter pin electrode and a ring
electrode. The arc burns freely at a fixed inter-electrode gap of 50 mm without
any forced gas flow. A resistive-capacitive branch parallel to the arc controls the
initial rate of rise of recovery voltage. By changing the parallel resistance, the
rate of rise of recovery voltage is varied from 9.8 V/μs to 84.8 V/μs. Time to reignition
and the corresponding re-ignition voltages are considered as the primary
parameters to characterize the thermal interruption performance. It is observed
that the re-ignition time rises with the decrease of rate of rise of recovery voltage
at all pressure levels, which is expected. However, in the absence of a forced gas
flow, high gas filling pressure results in a reduction of the time to re-ignition and
the re-ignition voltage in contrast to atmospheric pressure nitrogen arc.