8 b5 C- I" r% W! sQuestion: . H( D% s, V, l; f+ GClause 7.3 requires that the conductivity of the tracking test solution “be measured with alternating voltage at a frequency in the range 1 kHz to 2 kHz. The procedure is described in IEC 60589”. The procedure in IEC 60589 utilises conical flasks with reflux condensors, platinised platinum electrodes, a conductivity cell and a resistance bridge. This appears to be a chemical standard rather than an appropriate electrical test laboratory measurement technique. 6 k& o3 p8 o$ BAre CBTL: ( @: F6 h, z; Q- (a) expected to use this method of measurement for solution conductivity; or P; _/ D+ Q! x5 z- (b) can a suitable conductivity meter with a measurement frequency in the range 1 kHz to 2 kHz be used; or# ^- p* x6 R/ G( D6 I
- (c) can any suitable conductivity meter (different measurement range) be used.* Z; l3 @9 |: J0 `( h9 }' l8 _
Decision: 0 {7 P+ Y f4 r+ m: ^8 s! aThe Group decided that the “use of any appropriate conductivity meter with sufficient accuracy and uncertainty including the probe” is the only practical one - item (c) above. s; C+ k6 x# T! P8 r7 s8 ^& `- J) Q C- S
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DSH 724