Measurements

\--l

The type CDGl1 relay is a heavily9t.ped induction disc unit with aninverse definite minimumtime/current characteristic. The relaygives selective phase and earth faultovercurrent protection in timegraded systems to transformers, a.c.machines and feeders, etc., and' ensures that a minimum number of'\- circuit breakers are tripped to cleara faulted section (see ApplicationSheet R-50871.

The operating coil is wound to givetime/current curves of the sameshape on each of seven current tapswhich are selected by a plug settingbridge. The highest current tap is

\-, automatically selected when theplug is removed, so thatadjustments can be made on loadwithout open-circuiting the currenttransformerThe relay has a high torquemovement to ensure consistenttiming even under adverseconditions, and a low burden andovershoot. Adjustment of the timesetting is made by rotating aknurled moulded disc against a

\-/ graduated time multiplier scale.A high set overcurrent unit (typeCAG ) can be fitted in the same caseto provide instantaneous protectionunder maximum short circuitconditions (see Application SheetR-5097).The type CDG21 relay is either a,double pole version (with two earthfault units or two ovEr-current units)of the type CDG11, oi type CDG11with an instantaneous unit.

-Tfre type CDG31 relay is a triple poleversion (with fhree overcurrent unitsor two overcurrent units and oneearth fault unit in the centre) of typeCDG11.

\-,

AccuracyThe relay is calibrated at 50 Hz or60 Hz and 20"C and falls into errorclass index E7.5 as given inB.S. 142:1966. \

Frequency ErrorLess tha n 8o/o for frequencyvariation of 2 cycles; the timegrading of a protective systemwould be unaffected by this errorsince all the relays would besimilarly affected.Temperature ErrorFor an overload equal to 10 timesthe current setting, the percentagetiming errors at +45'C and -b'Carerespectively:1 3 second relay ..... -4o/o and *4o/o3'0 second relay ...r. -3o/o and *4o/o

Auxiliary units and operationindicatorsShunt reinforcing or series seal inauxiliary attracted armature unitswith a hand reset operationindicator can be fitted. Relayssupplied without an auxiliary unithave a hand reset operationindicator mechanically operated bythe disc.Standard coil ratingsVoltage operated (shunt) auxiliaryunits: 30, 110, 125 or 220 V d.c. at anominal burden of 3 Wcontinuously rated.

InuErsE IlmE OuErrurrentundEurth FuultFeluyIurEr tllE ll[hdlDElE

Current SettingsEqually Spaced Tap Ranges10400/", 20407" or 50-200Y" of 0.5,1 .0 or 5.0A 50 or 60 H z adjustable inseven equal steps.Graded Tap Ranges1040"/", 20407" or 50-200% of 0.5,1 '0 or 5.0A and 30-120o/o or80-320o/o of 5A, 50 or 60 Hzadjustable in seven unequal stepsas follows: 25/", 30o/o, 37.57", 50o/o,60o/o, 75o/" and 100% of top tapvalue.Starting Current103-105Y" of current settingClosing Current1150/" of current setting (117"/" whenfitted with a mechanical operationindicator)Resetting CurrentThe maximum current up to whichthe disc will completely reset is 90%of current setting.Time settingsH'3 seconds at 10 times currentsetting or 0-3.0 seconds at 10 timescurrent setting (8.5.142 :1966)Resetting TimeWith the time multiplier set at 1.0the resetting times of the above arefour seconds and nine second'srespectively.Overshoot .!On removal of a current equal to 20times current setting the overshoottimes of the ahove are 0.065 secondand 0.04 second respectively.BurdensStandard (3 VA nominal)-

2 VA at current setting onlowest tap3'5 VA at current setting onhighest tap

Alternative with lower operatingtorque

(t VA nominal)-0 75 VA at current setting onlowest tap1 3 VA at current setting onhighest tap

Thermal RatingThe relay will withstand twice thesetting current continuously and 20times the maximum setting currentfor three seconds.

Iures tllE llohdlDElE

t.0

0'9

0.8

0'7

0'6

0'5

0'4

0'3

0'2

r-0

0'9

0'8

0.7

0'6

0'5

0.4

0.3

0-2

v\,;,

\/

\r/

\-../

\

315678MULTTpLEs oF ir-uc sETTTNG

9 t0

CURRENT

45MULTIPLES

6 7 8 9 10

OF PLUG SETTING CURRENT

o15

0'r

0.35

.12

G

= o2s

gUJ

202o!r.Jo-r 0.15

:I.1ol;U

i '08ou,a-

'' .06

6 8 10 12 1,f 16 18

MULTIPLES OF PLUG SETTING CURRENT

r0

9

I7

6

V'Ulljv,

zl..rJ:tr10u 0'9zp o'8

fr o'to-o

o'o

0.5

ttl

TJLUvl

zIJtF

uztrd.lIIo-o

1.0

0.

0'8

0'7

0'6

25 A TAP,75 A50 A

6.2s A7s A8.75 A

1o.o A

\-

L./

\r'

\-'

Cu rre ntu n its:

operated (series) auxiliary

TRIPcorL

<.- RELAY CASE TERMINAL

T NORMALLY cLoSED cONTAcr

-Es- NORMALLY OPEN CONTACT

A.C. Trip circuitWhere a tripping supply is notavailable, a modified relay can besupplied which trips the circuitbreaker directly using current fromthe line transformer. The a.c.tripping circuit incorporates acurrent transformer and aninstantaneous unit which will safelycontrol a.c. trip coil currents up to150 A at 150 V Applications wherethe trip current exceeds this valuecan also be catered for

Relays are supplied in drawout casesdesigngd for, either flush or projectingmounting. Case wrappers aremanufactured from hot dippedgalvanised steel with a black pvc outercoating. These cases offer manyadvantages including ease ofmaintenance and testihg, and are fittedwith a contact which short circuits theassociated current transformer onwithdrawal of the unit. A filter is fittedwhich equalises the pressure insideand outside the case without admittingdust.Relays comply with 56 day humidityrequirements as specified in BS201 1

and lEC68. Climatic Category 20150156.

Minimum 0.5 secondoperating currentcurrent in A rating in A(two taps)

Coil resistancein ohms

v

0'1 and 0 3 18 and 220.2 and 2.0 22 and 9206and24 92""and188

9'2 and 2.1

6.0 and 0.1250'29 and 0.031

Qther coil rating#can be suppliedfor both Wpes of auxiliary unlt.GontactsOne or two electrically separatenormally-open self or hand resetcontacts are fitted which will makeand carry 7500 VA for 0.b secondwith maxima of 30 A and OO0 V a.c.or d.c.Relays supplied without an auxiliaryunit have one or two pairs ofnormally-open self reset contactswhich will make and carry 2500 VAfor 0.5 second with maxima of 10 Aand 660 V a.c. or d.c. The twocontact relay has a modifieddisc/contact assembly and isdesignated CDG16, CDG26 orcDG36.

I NSTANTAN EOUSUN IT

Earthing arrangementsAlthough not included in thediagram, it is assumed thatsecondary C.T and/or VT circuitswill be earthed as necessary incompliance with standard safetyrequirements and determined bythe switchgear contractor user. lf indoubt, please consult GECMeasurements for advice.lnsulatonThe relay will withstand 2'0 kVr.m.s. a.c. 50 Hz for 1 minutebetween all live parts and earth andand between all circuits notintended to be connected together.It will also withstand 1 kV r.m.s. a.c.50 Hz for 1 minute across opencontacts.

Relay typeCurrent setting rangeCurrent transformer second aryratingCharacteristic (time setting )

BurdenTrip circuit (series seal in, shuntreinforcing or a.c. )

Trip circuit current (series seal in)Trip circuit voltage (shuntreinforcing )

Operation indicator inscription ifrequiredAuxiliary contacts (hand or selfreset)Details of instantaneous unit (CAG)if requiredCase mounting

Max. Overall Dimensions'

Relay Case Height Width Depth*

mm mm mm

CDG1 1

CDG21 1D 237 173 218

Dimensioned drawings of. caseoutlines, panel cut-outs andmounting details are available onrequest.

CDG21 2D(double (Vert. )

pole)

425 174 218

\-.

\-/

3D 527(Vert. )

174 218

CDG313D(Horiz. )

458 218

*Add 7 mm for maximum length of M5terminal screws.

T2

10

C.T. SHORTINGCONTACTS

NOTEALL THREEELEMENTS ARETHE SAME ANDONLY ONE IS SHOWN.ALARM AND TRIP CCTSARE PARALLELED

TRIP CCT.ISOLATOR

THREE PHASE OVERCURRENT PROTECTION

Our policy is one of continuous product development and the right is reserved to supply 6quipmentwhich mayvary slightlyfrom thatdescribed.

GEG MeaCUfenentC The General Electric company, p.t.c,, of Engtand

St. Leonards Works Stafford ST17 4LX England

Telephone: 0785 223251 Fax: 0785 212232

C.T. CONNECTIONSFOR OVERCURRENTAND'EARTH FAULTPROTECTION

Publication R-5090GTelex: 36240 Cables : Measu rements Stafford

n2aTen ICA Drinfar,l i^ E^^la^.1