Compliance West MegaPulse 1.2x50-12.3PF-1, Instruction Manual

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Figure A 3. Actual output showing the arc being extinguished as the contact is closing.
The reason the output voltage drops more quickly when the ARC is extinguished can be understood by
reviewing the circuit schematic in
Figure A 1 : While there is an arc, C1 is connected in the circuit, and the
RC time constant is: (Rc + R2) x (C1 + C3). When the arc is extinguished, the circuit has a shorter time
constant: (Rc + R2) x (C3).
As soon as the arc is extinguished, a high impedance exists again between the COM contact and the NO
contact. Therefore a voltage difference will again develop between the two contacts. Keep in mind that at
the same time, the contacts are still approaching each other at speed V:
at some point before the contacts
close, the contact gap will be small enough that breakdown may again occur across the contact gap . This
arcing - extinguish - re-arcing cycle may repeat more than once during the switching time. This condition is
shown in
Figure A 4 .