Arc Suppression Factor

Arc Suppression Factor (ASF)
Arc suppression methods and devices may be compared using an Arc Suppression Factor (ASF), measuring the ratio of the arc energy without suppression (W_{no a/s}) over the arc energy with suppression (W_a/s) as follows:

          ASF = W_{no a/s} / W_a/s

The ASF allows arc suppression devices to be objectively compared as follows:
   ASF = 1 ......... No Effect
   ASF > 1 ......... Positive Effect (i.e., arc energy is decreased)

Using the examples shown on the Suppression Measures page (here), based on the findings in Lab Note 103 (here), yields the following example calculation:

AC Power ASF Calculation

AC power arc without arc suppression
The break arc lasts about 7ms as shown, until the current approaches the zero-crossing. Looking at this scope picture you can almost “feel” the arc burn through the widening contact air gap.

W_arc0(unsuppressed arc energy) ≈ 437mJ
Calculation: W_arc0 = I_arc0 x V_arc0 x T_arc0
Mean I_arc0 ≈ 2.5A
Mean V_arc0 ≈ 25V
Mean T_arc0 ≈ 7ms

AC power arc with NOsparc arc suppression
The break arc is arrested as it forms, and is suppressed approximately 7ms until the current approaches the zero- crossing. We refer to this initially arrested arc as an "arclet."

W_arclet(arclet energy**) ≈ 350µJ
Calculation: W_a/s = I_a/s x V_a/s x T_a/s
Mean I_a/s ≈ 2.5A
Mean V_a/s ≈ 2V
Mean T_a/s ≈ 7ms
** Energy in the initial, nascent arc just prior to suppression

The ASF calculation for an arc suppressed by NOsparc technology is:

ASF ≈ 1250 ... A Very Significant Effect

Where:
ASF = W_arc0 ÷ W_arclet
Mean W_arc0 ≈ 437mJ; Mean W_arclet ≈ 350μJ