XITRON XT2640 - Ch ) or 3 Ø 4 W Wiring Using External Current Measurement; Mechanical (Motor) Measurement Wiring

XT2640OperatingManual 13July2016 Page26of187
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9.7 3Ø3W(3CH)OR3Ø4W WIRINGUSINGEXTERNALCURRENTMEASUREMENT
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CAUTION:
 FORANA:ATYPECT:USEWITHSH,SD,AH,AD,LH,LD,WHORWDCHANNELSONLY
 FORANA:VTYPECTORASHUNT:USEWITHSX,AX,LXORWXCHANNELSONLY
 DONOTCONNECTWIRINGWHILEVOLTAGEPRESENT.
 ENSURE
WIRINGISCORRECTBEFOREAPPLYINGVOLTAGE.
WIRING:
 Thickerconnectionsarecurrentcarrying.Ensurewireusedisratedforthemaximumvoltageandcurrenttobe
encountered.
 Thinnerconnectionsarenotcurrentcarrying.Ensurewireusedisratedforthemaximumvoltagetobeencountered.
 Phasesareshownfordescriptivepurposes,theXT2640placesnorelianceontheactualphasinghoweverusingthose
shownensuresthattheXT2640displaymatchestheactualphasingifthechannelshaveincreasingchannelnumbersfrom
lefttorightinthediagramabove.
 ManyCTdevicesareisolating,inthosecasesyoushouldgroundtheA‐(BLUE)terminalofthechanneliftheCTdoesnot
groundit.
XT2640CONFIGURATION:
 IntheXT2640MEASCONFIGmenuyoushouldappropriatelysetSCALEforeachchanneltosuittheCTorshuntbeingused
(bothascalefactorandanoffsetareavailable).
9.8 MECHANICAL(MOTOR)MEASUREMENTWIRING
Mechanicalmeasurementresultsarebasedonone,twoorthreesignalsprovidedtotheMTtypechannelinstalledintheCH4
location.Thesecanbemeasurementsofeitheramotororagenerator.
InallcasestheBNCconnectorsprovidedontheMTchannelareassumedtobeatavoltageclosetogroundontheiroutershield,
voltagesofupto13VpkfromtheXT2640chassisareaccommodated.
Note:
Ifonlyoneofspeedandtorqueareavailablethenmechanicalpowercannotbecomputedandisnotavailable,howeverthe
onesignalconfiguredwillbeavailable.
Ifthespeedofthemotorisfixedandisexactlyknownandisnotmeasured,thenthiscanbeaccommodatedbysettingthe
SPDinputasanalogandconfiguringitwithzeroscalingandsettingtheoffsettotheactual,known,speedofthemotor.In
thismannerthemechanicalpowerwillbeavailablefromtheXT2640eventhoughspeedisnotactuallymeasured,however
themechanicalpowerindicatedwillbeaffectedbytheaccuracyoftheknownspeedofthemotor.
Similarly,ifthespeedofthemotorisknowntobeamultipleoftheelectricaldrivefrequency(orgeneratedelectrical
frequency)thenthiscanalsobeusedinsteadofanactualmotorspeedinputbyconfiguringtheXT2640tocompute
mechanicalspeedfromtheelectricalfrequencyofaVPA,howevertheaccuracyofthemechanicalspeed,andthusthe
mechanicalpower,maybeaffectedbyerrorssuchasmotorslip.
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A
V

XT2640
C
H
CT
+ -
øA
From
SOURCE
øA
To
LOAD
A
V

XT2640
CH
CT
+ -
øB
From
SOURCE
øB
To
LOAD
A
V

XT2640
CH
CT
+ -
øC
From
SOURCE
øC
To
LOAD
N
From
SOURCE
N
To
LOAD
For 3ø3w(3ch) only
Each V- terminal is connected together as shown but there is no N SOURCE or LOAD
connection. The V- terminals may optionally be grounded