49
DEVELOPMENT, MANUFACTURING AND SUPPLY OF INSTRUMENTATION
5.. The. “double”. scale. shows.
levels.
(amplitudes).
of.
the.
frequency. components. of. the.
signal.. At. bottom. -. “A8kHz”,. at.
top. -. “A1kHz”.. When. levels. of.
the. frequency. components. are.
insufficient. for. determination.
“
Δφ”
,. the. inscriptions. “A8kHz”.
and.“A1kHz”.are.correspondingly.
“darkening”,. and. the. value.
“X.XdB”.disappears.
6.. There. is. no. need. to.
continuously. move. along. the.
route,. controlling. the. signal..
You.can.walk.around.the.place.
which.is.hard.to.reach..If,.while.
returning. to. the. route,. A8/A1.
did. not. changed,. it. means.
that.there.are.no.damages.on.
the.surveyed.site.
7...The.sharp.positive.overfall.of.the.“A8/A1”.value.by.3dB.and.more.indicates.the.possibility.of..
defect.existence.(the.resistance.is.less.than.5.kOhm)..The.sensor.should.be.located.straight..
across.the.utility..
If.you.go.through.the.same.site.in.the.opposite.direction..
(towards.the.generator),.holding.the.receiver.the.same.as..
before.with.reset.of.the.indication.(using.the.button.
),..
negative.values.of.the.reading.(more.than.minus.3dB).will..
mean.that.there.is.damage.in.the.cable.
2. Phase “two-frequency” Method “
Δφ”
The..contactless..method..of..search..for..insulation..defects..of..city..cables..with..resistance..
less..than.10.kOhm..The.smaller.the.distance.from.the.end.of.the.cable,.the.higher.the.sensitivity.
of.the..method.on.this.site..This.method.cannot.be.used.in.a.city.because.of.high.distortion.of.the.
signal..
Steps.1-3.
are.similar.
to.those.
in.p.3.
4. .. “
Δφ
”. . shows. the. . change. . of. . the. . phase..
difference.“
φ
1024..–..
φ
8192”,.after.the.resetting..
(in. degrees. . reduced. to. the. . frequency. . 1024..
Hz)..The..value..“
Δφ
”..sharply..changes,..when.
the.operator..passes..the..place..of..leakage..of..
the..signalling.current.into.the.ground..
NOTE
Δφ
indication.. can.. be.. negative,.. “running”.. in..
the..process..of..increase..of..distance.from..the..
generator.. It. is. recommended. to. periodically..
reset..such..indications..(exactly..over..the..route),..
using.the.button.
.
5..
The.
“doubled”.
scale.
shows. . . . levels. (amplitudes). of..
the. . frequency. components. of..
the. . signal.. At. . bottom. . -. . A8kHz,..
at. top. . -. . A1kHz.. When. . levels. of..
the. . frequency. components. . are..
insufficient.
for.
determination..
A8/A1,. the. . inscriptions. . A8kHz..
and. . A1kHz. . are. . correspondingly..
“darkening”,..and..the..value..“X
0
”.
disappears.
6..There..is..no..need..to..
continuously. . move. . along..
the. . route,. controlling. . the..
signal..You.can.walk.around..
the..place.which..is..hard..to..
reach.. If,. . while. . returning..
to. . the. . route,. . A8/A1. . did..
not..change,..it.means..that..
there. . are. no. damages. on..
the.surveyed.site..
Содержание AG-309.15G
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