3M Dynatel 2250M - Pinpointing the Buried Fault

78-8130-6150-0-F 37
5. Presson: Ohm-meter/Fault Locate/Tone [T-2]toturnthetransmitteronandplace
thetransmitterinOhm-metermode.
− TheresistanceofthefaultwillbedisplayedinohmsonthetransmitterDigital
Display[T-4].
− Resistancelessthan50KΩ=Significantfaultexists
− Resistance50KΩto1.0MΩ=Highresistancefaultexists(Mayormaynot
causeproblemsyet,butgetsworsewithtime.)
− Resistancegreaterthan1.0MΩ=Nosignificantfaultexists
Note: The fault locating limit is 2.0MΩ, although the transmitter's ohm-meter mode
can display a fault resistance up to 10MΩ.
− Note:Thefaultlocatinglimitis2.0MΩ,althoughthetransmitter'sohm-meter
modecandisplayafaultresistanceupto10MΩ.
6. Presson: Ohm-meter/Fault Locate/Tone [T-2]again,toselectFaultLocatemode.
− TheIndicatorFlagwillturnonunderthefaulticonintheDigitalDisplay[T-4]
(asshownintheillustrationbelow)
B. Pinpointing the Buried Fault
1. Connectthe3M
™
Dynatel
™
EarthContactFrame(alsoknownasanA-Frame)tothe
External Jack[14]([13]on2250M)ofthereceiverusingtheearthframecable(4
ft.(1.2m)cable).
2. PressOn/Off (Power) [1]topoweronthereceiver.Thereceiverdisplayscreenwill
display"Fault Calibrating"forabout5seconds.
3. PressLocate/OK [5].
4. PressFault [SK]toselectFaultmode.
5. HoldthereceiverinonehandandtheEarthContactFrameintheotherwiththe
solidgreen-bandedlegoftheframetowardthetestsection.Nearthelocationof
thegroundrod(aboutoneEarthContactFramewidthawayfromthegroundrod,
slightlytothesideandtowardsthefaultedcable),inserttheEarthContactFrame
probesfullyintothegroundinlinewiththetargetpath.
6. PressRef [SK]torecordthefaultlevelreferencesignal.Thesignallevelwillbe
recordedintheboxaboveRef[SK]onthedisplay.Thisreferenceindicatesthe
Signal Strength[10]levelatthegroundrod.Whentheoperatorreachesthemajor
faultlocation,theSignal Strength[10]indicatedonthereceiverwillbeveryclose
(within12dB)tothisreferencesignallevel.