Medium Voltage Devices _ Range Products

Siemens Power Engineering Guide · Transmission & Distribution2/66

Medium-Voltage DevicesProduct Range

Devices formedium-voltage switchgear

With the equipment program for switch-gear Siemens can deliver nearly everydevice which is required in the medium-voltage range between 7.2 and 36 kV.Fig. 110 gives an overview about the avail-able devices and their main characteristics.All components and devices conform tointernational and national standards,as there are:

Vacuum circuit breakers

■ IEC 56■ IEC 694■ BS5311■ DIN VDE 0670

Vacuum switches

■ IEC 265-1■ DIN VDE 0670, Part 301in combination with Siemens fuses:■ IEC 420■ DIN VDE 0670, Part 303

Vacuum contactors

■ IEC 470■ DIN VDE 0660, Part 103■ UL 347

Switch disconnectors

■ IEC 129■ IEC 265-1■ DIN VDE 0670, Part 2■ DIN VDE 0670, Part 301

HV HRC fuses

■ IEC 282■ DIN VDE 0670, Part 4

Current and voltage transformers

■ IEC 185, 186■ DIN VDE 0414■ BS 3938, 3941■ ANSI C57.13

For further information please contact:

Fax: ++ 49 - 91 31 - 73 46 54

Fig. 110: Equipment program for medium-voltage switchgear

Short-timecurrent(3s)

[kA]

3AH

3AF3AG

Type Ratedvoltage

[kV]

Short-circuitcurrent

[kA]

Indoor and outdoorcurrent and voltagetransformers

Device

Indoor vacuumcircuit breaker

Outdoor vacuumcircuit breaker

Modular assembly setwith indoor VCB

Indoor vacuum switch

Indoor vacuumcontactor

Vacuum interrupter

Indoor switchdisconnector

Indoor disconnectingand grounding switch

HV HRC fuses

Fuse bases

Indoor post insulators,bushings

7.2 … 36

12, 36

7.2 … 15

7.2 … 24

3.6 … 12

7.2 … 40.5

7.2 … 24

7.2 … 36

7.2 … 36

7.2 … 36

3.6 … 36

12 … 36

3CG

3TL

VS

3CJ

3D

3GD

3GH

3FA

3M

13.1 … 63

25

25 … 44

–

–

12.5 … 72

–

–

31.5 … 80

–

–

13.1 … 63

25

25 … 44

16 … 20

8 (1s)

12.5 … 72

16 … 20 (1s)

16 ... 63 (1s)

–

–

–

–

44peak withstandcurrent

Siemens Power Engineering Guide · Transmission & Distribution 2/67

Medium-Voltage DevicesProduct Range

PageRatedcurrent

[A]

2/68�

2/72

2/73

2/74

2/76

2/77

2/78

2/79

2/80

2/80

2/81

2/82

mechanical

Applications/remarksOperating cycles

All applications, e.g. overhead lines, cables, transformers,motors, generators, capacitors, filter circuits, arc furnaces

All applications, e.g. overhead lines, cables, transformers,motors, generators, capacitors, filter circuits

Original equipment manufacturer (OEM) and retrofit

All applications, e.g. overhead lines, cables, transformers,motors, capacitors; high number of operations; fusesnecessary for short-circuit protection

All applications, especially motors with very high numberof operating cycles

For circuit breakers, switches and gas-insulated switchgear

Small number of operations, e.g. distribution transformers

Protection of personnel working on equipment

Short-circuit protection; short-circuit current limitation

Accommodation of HV HRC fuse links

Insulation of live parts from another,carrying and supporting function

Measuring and protection

with ratedcurrent

with short-circuit current

25 … 100

30 … 50

–

–

–

25 … 100

–

–

–

–

–

–

10,000 …30,000

10,000

–

10,000

0.25x105 ... 2x106

10,000 …30,000

800 … 4000

1600

1250 … 3150

800

400 … 450

800 … 4000

630

400 … 2500

6.3 … 250

400

–

–

20

–

–

–

–

–

1000

–

–

–

–

–

10,000 …120,000

10,000

–

10,000

1x106 ... 3x106

10,000 …30,000


Indoor vacuum circuit breakerstype 3AH

The 3AH vacuum circuit breakers arethree-phase medium-voltage circuit break-ers for indoor installations.As standard circuit breakers they are avail-able for the entire medium-voltage range.Circuit breakers with reduced pole centerdistances, circuit breakers for very highnumbers of switching cycles and single-phase versions are part of the program.The following breaker types are available:■ 3AH1 – the maintenancefree circuit

breaker which covers the rangebetween 7.2 kV and 24 kV. It hasa lifetime of 10,000 operating cycles

■ 3AH2 – the circuit breaker for 60,000operating cycles in the range between7.2 kV and 24 kV

■ 3AH3 – the maintenancefree circuitbreaker for high breaking capacities inthe range between 7.2 kV and 36 kV.It has a lifetime of 10,000 operatingcycles

■ 3AH4 – the circuit breaker for up to120,000 operating cycles

■ 3AH5 – the economical circuit breaker inthe lower range for 10,000 maintenance-free operating cycle

The 3AH circuit breakers are suitable for:■ Rapid load transfer, synchronization■ Automatic reclosing up to 31.5 kA■ Breaking short-circuit currents with

very high initial rates of rise of the recov-ery voltage

■ Switching motors■ Switching transformers and reactors■ Switching overhead lines and cables■ Switching capacitors■ Switching arc furnaces

Fig. 111: The complete 3AH program

Rated short-circuit breakingcurrent [kA]

7.2

12

15

17.5

24

36

13.1 16 20 25 31.5 40 50 63

800 800-1250

800-2500

800-1250

1250-3150

1250-4000

1250-2500

–-2500

Rated voltage[kV]

3AH1 3AH2 3AH3 3AH4 3AH5

800-1250

800-1250

1250-3150

Rated current[A]

Medium-Voltage DevicesType 3AH

Properties of 3AH circuit breakers:

No relubrication

Nonwearing material pairs at the bearingpoints and nonaging greases make relubri-cation superfluous on 3AH circuit breakersup to 10,000 operating cycles, even afterlong periods of standstill.

High availability

Continuous tests have proven that the3AHs are maintenancefree up to 10,000operating cycles: accelerated temperature/humidity change cycles between –25 and+60 °C prove that the 3AH functions relia-bly without maintenance.

Assured quality

Exemplary quality control with some hun-dred switching cycles per circuit breaker,certified to DIN/ISO 9001.

No readjustment

Narrow tolerances in the production ofthe 3AH permanently prevent impermissi-ble play: even after frequent switchingthe 3AH circuit breaker does not need tobe readjusted up to 10,000 operatingcycles.


Fig. 112: Vacuum circuit breakers type 3AH

Fig. 113: Front view of vacuum circuit breaker 3AH1 with 160-mm pole center distance. Available up to 17.5 kV


Advantages of thevacuum switching principle

The most important advantages of theprinciple of arc extinction in a vacuum havemade the circuit breakers a technically su-perior product and the principle on whichthey work the most economical extinctionmethod available:■ Constant dielectric:

In a vacuum there are no decompositionproducts and because the vacuum inter-rupter is hermetically sealed there areno environmental influences on it.

■ Constant contact resistance:The absence of oxidization in a vacuumkeeps the metal contact surface clean.For this reason, contact resistance canbe guaranteed to remain low over thewhole life of the equipment.

■ Large total current:Because there is little burning of con-tacts, the rated normal current can beinterrupted up to 30,000 times, theshort-circuit breaking current an averageof 50 times

■ Small chopping current:The chopping current in the Siemensvacuum interrupter is only 4 to 5 A dueto the use of a special contact material.

■ High reliability:The vacuum interrupters need no seal-ings as conventional circuit breakers.This and the small number of movingparts inside makes it extremely reliable.


Fig. 114a: Dimensions of typical vacuum circuit breakers type 3AH (Examples)

604532

210 210

520

190

105

437 473

60

604538

210 210

565

109

437583

105

190550

275 275662708 565

190

105

437535

60

Dimensions in mm

Dimensions in mm

Dimensions in mm

20 kA, up to 1250 A25 kA, up to 1250 A

3AH1,12 kV

16 kA, up to 1250 A,20 kA, up to 1250 A,25 kA, up to 1250 A

3AH1,24 kV

31.5 kA, 2500 A,40 kA, 2500 A

3AH1, 3AH2,12 kV



708 595670

275275190

105

437

109

610

648

211 483

564 733

750275 275

25 kA, 2500 A

63 kA, 4000 A

3AH3,12 kV

31.5 kA, 2500 A,40 kA, 2500 A

3AH1, 3AH2,24 kV

3AH3, 3AH4,36 kV

776

820350 350

853

526211

612

564 1000791

Dimensions in mm

Dimensions in mm

Dimensions in mm


Fig. 114b: Dimensions of typical vacuum circuit breakers type 3AH (Examples)


Outdoor vacuum circuitbreakers type 3AF and 3AG

The Siemens outdoor vacuum circuitbreakers are structure-mounted, easy-to-install vacuum circuit breakers for use insystems up to 36 kV. The pole construc-tion is a porcelain-clad construction similarto conventional outdoor high-voltageswitchgear. The triple-pole circuit breakeris fitted with reliable and well proven vacu-um interrupters. Adequate phase spacingand height have been provided to meetstandards and safety requirements.It is suitable for direct connection to over-head lines.The type design incorporates a minimumof moving parts and a simplicity of assem-bly assuring a long mechanical and electri-cal life. All the fundamental advantages ofusing vacuum interrupters like low operat-ing energy, lightweight construction, vir-tually shockfree performance leading toease of erection and reduction in founda-tion requirements, etc. have been retained.The Siemens outdoor vacuum circuitbreakers are designed and tested to meetthe requirements of IEC 56/IS 13118.

Advantages at a glance

■ High reliability■ Negligible maintenance■ Suitable for rapid autoreclosing duty■ Long electrical and mechanical life■ Completely environmental-friendly

Fig. 115: Outdoor vacuum circuit breakertype 3AF for 36 kV

Fig. 117: Dimensions of outdoor circuit breaker type 3AF for 36 kV

Fig. 116: Ratings for outdoor vacuum circuit breakers

12Rated voltage

Rated frequency

Rated lightning-impulse withstand voltage

Rated power-frequencywithstand voltage (dry and wet)

Rated short-circuitbreaking current

Rated short-circuitmaking current

Rated current

75

28

25

63

1600

50/60

36

170

70

25

Type 3AG

Technical data

Type 3AFVacuum circuit-breaker type

50/60

63

1600

[kV]

[Hz]

[kV]

[kV]

[kA]

[kA]

[A]

1830

1217

725 725190

19301730

650450

31052510

3710 3748

285 285

Front view Side view

Dimensions in mm

Medium-Voltage DevicesType 3AF/3AG


Modular assembly sets withindoor vacuum circuit breakers

The modular assembly sets are especiallysuitable for retrofit applications and for theuse by original equipment manufacturers(OEM).The withdrawable assembly sets consist ofparts of type-tested, metal-clad, air-insulat-ed medium-voltage primary distributionswitchgear. The circuit-breaker compart-ment can be integrated in the completebay as individually required.The centerpiece of the set is a medium-voltage vacuum circuit breaker, incorporat-ing all benefits of vacuum switchgeartechnology:■ High reliability■ Negligible maintenance■ Long electrical and mechanical life■ Completely environment-friendly■ Suitable for all switching dutiesUse of these parts allows the OEM to uti-lize Siemens know-how in the constructionof air-insulated switchgear, with all the con-sequent advantages, such as:■ Components type-tested to IEC, devel-

oped and manufactured to DIN/ISO 9001■ Maximum flexibility in the manufacturing

process■ Wide product range

Ratingsfor withdrawable truck shown in Fig. 118

7.2 kV to 15 kV rated voltage1250 A to 3150 A rated current25 kA to 44 kA rated short-circuit

breaking current

Fig. 118: Withdrawable truck with vacuum circuit breaker (Example)

Medium-Voltage DevicesModular Assembly Sets


Indoor vacuum switchestype 3CG

The 3CG vacuum switches are multipur-pose switches conforming to IEC 265-1and DIN VDE 0670 Part 301.With these, all loads can be switched with-out any restriction and with a high degreeof reliability. The electrical and mechanicaldata are greater than for conventionalswitches. A rated current of 800 A, forexample, can be interrupted 10,000 timeswithout maintenance.The operating mechanism needs to belubricated only every 10 years.The vacuum switch is therefore extremelyeconomical.Vacuum switches are suitable for thefollowing switching duties:■ Overhead lines■ Cables■ Transformers■ Motors■ Capacitors■ Switching under ground-fault conditions

3CG switches can be combined with allSiemens fuses (250 A) and comply withthe specifications of IEC 420 andDIN VDE 0670 Part 303.

Fig. 119: Ratings for vacuum switches type 3CG

Fig. 120: Vacuum switch type 3CG for 24 kV, 800 A

Medium-Voltage DevicesType 3CG

Rated voltage U

Rated lightning-impulsewithstand voltage Ul,

Rated short-circuit makingcurrent I ma

Rated short-time current I m (3s)

Rated normal current I n

Rated ring-main breakingcurrent I c 1

Rated transformer breaking current

Rated capacitor breaking current

Rated cable-chargingbreaking current I c

Rated breaking current forstalled motors I d

Inductive switching capacity(cos ϕ ≤ 0.15)

Switching capacity underground fault conditions:– Rated ground fault breaking current I e– Rated cable-charging breaking current– Rated cable charging breaking current with superimposed load current

Number of switching cycles with I n

[kV]

[kV]

[kA]

[kA]

[A]

[A]

[A]

[A]

[A]

[A]

[A]

[A][A]

[A]

Technical data

12

75

50

20

800

800

10

800

63

1600

1600

63063

63+800

10,000

15

95

50

20

800

800

10

800

63

1250

1250

63063

63+800

10,000

24

125

40

16

800

800

10

800

63

–

1250

63063

63+800

10,000

7.2

60

50

20

800

800

10

800

63

2500

2500

63063

63+800

10,000


Fig. 121: Dimensions of vacuum switch type 3CG (Examples)

7.2 and 12 kV switch

24 kV switch

630

275 275

379

684

708

537

435

43170

597

530

264

210 210

568

592

435

43170

492

482

Dimensions in mm

Dimensions in mm

Medium-Voltage DevicesType 3CG


280 mm

325 mm

340 mm

Fig. 122: Vacuum contactor type 3TL6 for fixedmounting

Vacuum contactorsType 3TL

The three-pole vacuum contactors type3TL are for medium-voltage systems be-tween 3.6 kV and 12 kV and incorporate asolenoid-operated mechanism for highswitching frequency and unlimited closingduration.They are suitable for the opera-tional switching of AC devices in indoorsystems and can perform, for example, thefollowing switching duties:■ Switching of three-phase motors in

AC-3 and AC-4 operation■ Switching of transformers■ Switching of capacitors■ Switching of ohmic loads

(e.g. arc furnaces)

3TL vacuum contactors have the followingfeatures:■ Small dimensions■ Long electrical life

(up to 106 operating cycles)■ Maintenancefree■ Vertical or horizontal mounting

The vacuum contactors comply with thestandards for high-voltage AC contactorsbetween 1 kV and 12 kV according to IECPublication 470-1970 and DIN VDE 0660Part 103.3TL contactors also comply with ULStandard 347.

The vacuum contactors are available indifferent designs:■ Type 3TL6 with compact dimensions

and an electrical lifetime of 1x106 operat-ing cycles

■ Type 3TL8 with slender design and anelectrical lifetime of 0.25x106 operatingcycles

In the withdrawable unit, the 3TL6 vacuumcontactor can be grouped together andelectrically connected with fuse carriers forHV HRC fuse links according to DIN/BSand also with overvoltage limiters.

Fig. 123: Vacuum contactor type 3TL6 mounted onwithdrawable unit

Fig. 124: Ratings for vacuum contactors type 3TL

Medium-Voltage DevicesType 3TL

Fig. 125: Vacuum contactor type 3TL8 for fixedmounting

780 mm

1200 mm

605 mm

390 mm

375 mm

220 mm

Rated voltage Ue

Rated frequency

Rated normal current I e

Switching capacity according toutilization category AC-4 (cos ϕ = 0.35)Rated making currentRated breaking current

Mechanical life of the contactorswitching cycles

Mechanical life of the vacuuminterrupter – switching cycles

Electrical life of the vacuum interrupter(switching cycles with rated current)

Vacuum contactor type

[kV]

[Hz]

[A]

[A]

Technical data

12

3TL 65

7.2

3TL 61

3.6

50/60

45003600

3TL 60

7.2

50/60

40003200

3TL 81

450 400

1 x 106

1 x 106

1 x 106

3 x 106

2 x 106

1 x 106

3 x 106

2 x 106

1 x 106

1 x 106

0.25 x 106

0.25 x 106


Medium-Voltage DevicesType VS

Vacuum interrupters

Vacuum interrupters for the medium-volt-age range are available from Siemens forall applications on the international marketfrom 1 kV up to 40.5 kV.

Applications

■ Vacuum circuit breakers■ Vacuum switches■ Vacuum contactors■ Transformer tap switches■ Circuit breakers for railway applications■ Autoreclosers■ Special applications, e.g. in nuclear

fusion

Compact design

Vacuum interrupters providea very high switching capacity within verycompact dimensions: e.g. vacuum inter-rupters for 15 kV/40 kA with housingdimensions of 125 mm diameter by168 mm length or for 12 kV/12.5 kA with68 mm diameter by 124 mm length.

Consistant quality assurance

Complete quality assurance (TQM andDIN/ISO 9001), rigorous material checkingof every delivery and 100% tests of theinterrupters for vacuum sealing guaranteereliable operation and the long life ofSiemens vacuum interrupters.

Environmental protection

In the manufacture of our vacuum inter-rupters we only use environmentally com-patible materials, such as copper, ceramicsand high-grade steel.The manufacturing processes do not dam-age the environment. For example, noCFCs are used in production (fulfilling theMontreal agreement), the components arecleaned in a ultrasonic cleaning plant.During operation vacuum interrupters donot affect the environment and are them-selves not affected by the environment.

Know-how for special applications

If necessary, Siemens is prepared to sup-plement our wide standard program byway of tailored, customized concepts.

Fig. 126: Vacuum interrupters from 1 kV to 40.5 kV

Fig. 127: Range of ratings for vacuum interrupters

Interrupters for vacuum circuit breakers

Un

In

Isc

7.2 kV – 40.5 kV

800 A – 4000 A

12.5 kA – 72 kA

Interrupters for vacuum contactors

Un

In

1 kV – 12 kV

450 A


Technical data

7.2

20

50

630

Rated voltage

Rated short-timecurrent


Rated normal current

[kV]

[kA]

[kA]

[A]

12

20

50

630

15

16

40

630

24

16

40

630

Switch disconnectorstype 3CJ1

Indoor switch disconnectors type 3CJ1 aremultipurpose types and meet all the rele-vant standards both as the basic versionand in combination with (make-proof)grounding switches.The 3CJ1 indoor switch-disconnectorshave the following features:■ A modular system with all important

modules such as fuses, (make-proof)grounding switches, motor operatingmechanism, shunt releases and auxiliaryswitches

■ Good dielectric properties even underdifficult climatic conditions because ofthe exclusive use of standard post insu-lators for insulation against ground

■ No insulating partitions even with smallphase spacings

■ Simple maintenance and inspection

Fig. 128: Switch disconnector type 3CJ1

Fig. 129: Ratings for switch disconnectors type 3CJ1

Medium-Voltage DevicesType 3CJ1


Medium-Voltage DevicesType 3D

Technical data

12

16 to 63

40 to 160

400 to 2500

Rated voltage




[kV]

[kA]

[kA]

[A]

24

16 to 31.5

40 to 80

630 to 2500

36

20 to 31.5

50 to 80

630 to 2500

Fig. 130: Disconnecting switch type 3DC

Disconnecting and groundingswitches type 3D

Disconnecting and grounding switchestype 3D are suitable for indoor installationsfrom 12 kV up to 36 kV.Disconnectors are mainly used to protectpersonnel working on equipment and musttherefore be very reliable and safe.This is assured even under difficult climaticconditions.Disconnecting and grounding switchestype 3D are supplied with a manual ormotor drive operating mechanism.

Fig. 131: Ratings for disconnectors type 3DC

Fig. 132: Ratings for grounding switches type 3DE

Technical data

12

20 to 63

50 to 160

Rated voltage


Rated peakwithstand current

[kV]

[kA]

[kA]

24

20 to 31.5

50 to 80

36

20 to 31.5

50 to 80


HV HRC fusestype 3GD

HV HRC (high-voltage high-rupturing-capac-ity) fuses are used as a short-circuit protec-tion in high-voltage switchgear. They pro-tect switchgear and components, such astransformers, motors, capacitors, voltagetransformers and cable feeders, from thedynamic and thermal effects of high short-circuit currents by breaking them as theyoccur.The HV HRC fuse links can only be usedto a limited degree as overload protectionbecause they only operate with certaintywhen their minimum breaking current hasalready been exceeded. Up to this currentthe integrated thermal striker prevents athermal overload on the fuse when used incircuit breaker/fuse combinations.Siemens HV HRC fuse links have the fol-lowing features:■ Use in indoor and outdoor installations■ Nonaging because the fuse element

is made of pure silver■ Thermal tripping■ Absolutely watertight■ Low power lossWith our 30 years of experience in themanufacture of HV HRC fuse links andwith production and quality assurancethat complies with DIN/ISO 9001,Siemens HV HRC fuse links meet thetoughest demands for safety and reliability.

Fuse-bases type 3GH

3GH fuse bases are used to accomodateHV HRC fuse links in switchgear.These fuse bases are suitable for:■ Indoor installations■ High air humidity■ Occasional condensation3GH HV HRC fuse bases are available assingle-phase and three-phase versions.On request, a switching state indicatorwith an auxiliary switch can be installed.

Fig. 134: Ratings for HV HRC fuse links type 3GD

Fig. 133: HV HRC fuse type 3GD

Fig. 135: Fuse bases type 3GH with HV HRC fuse links

Fig. 136: Ratings for fuse bases type 3GH

Technical data

7.2

63 to 80

6.3 to 250

Rated voltage

Rated short-circuitbreaking current


[kV]

[kA]

[A]

12

40 to 63

6.3 to 160

24

31.5 to 40

6.3 to 100

36

31.5

6.3 to 40

Technical data

3.6/7.2

44

400

Rated voltage

Peak withstandcurrent

Rated current

[kV]

[kA]

[A]

12

44

400

24

44

400

36

44

400

Medium-Voltage DevicesType 3GD/3GH


Fig. 140: The principle of capacitive voltage indication with the 3FA4 divider post insulator

Medium-Voltage DevicesInsulators and Bushings

Insulators:Post insulators type 3FAand bushings type 3FH/3FM

Insulators (post insulators and bushings)are used to insulate live parts from one an-other and also fulfill mechanical carryingand supporting functions.The materials for insulators are variouscast resins and porcelains. The use ofthese materials, which have proved them-selves over many years of exposure to theroughest operating and ambient conditionsand the high quality standard to DIN/ISO9001, assure the high degree of reliabilityof the insulators.Special ribbed forms ensure high electricalstrength even when materials are deposit-ed on the surface and occasional conden-sation is formed.Post insulators and bushings are manufac-tured in various designs for indoor and out-door use depending on the application.Innovative solutions, such as the 3FA4divider post insulator with an integratedexpulsion-type arrester, provide optimumutility for the customer.Special designs are possible if requestedby the customer.

Fig. 137: Draw-lead bushing type 3FH5/6

Fig. 138: Post insulators type 3FA1/2

C1

V C2

M

A

L

U

U1

U2

LUU1

U2

ConductorOperating voltagePartial voltageacross C1Partial voltage acrossC2 and indicator

C1C2

VAM

Coupling capacitanceUndercapacitance

ArresterIndicatorMeasuring socket

12

65 to90

35 to50

3.75 to25

3.6

60 to65

27 to40

3.75 to16

24

100 to145

55 to75

3.75 to25

36

145 to190

75 to105

3.75 to16

Technical data

Normal voltage

Lightning-impulsewithstand voltage

Rated power-frequencywithstand voltage

Minimum failing load

[kV]

[kV]

[kV]

[kN]

Fig. 139: Ratings for post insulators type 3FA1/2


Technical data

12

10 to2500

80

Rated voltage

Primary ratedcurrent

Max. thermal ratedshort time current

Sec. thermallimit current

Current transformers Voltage transformers

[kV]

[A]

[kA]

[A]

24

10 to2500

80

36

10 to2500

80

12

5 to 10

24

5 to 13

36

8 to 17

Current and voltagetransformers type 4M

Measuring transformers are electricaldevices that transform primary electricalquantities (currents and voltages) to pro-portional and in-phase quantities which aresafe for connected equipment and operat-ing personnel.The indoor post insulator current and volt-age transformers of the block type haveDIN-conformant dimensions and are usedin air-insulated switchgear. A maximum ofoperational safety is assured even underdifficult climatic conditions by the use ofcycloalyphatic resin systems and provencast-resin technology.Special customized versions (e.g. up to3 cores for current transformers, switcha-ble windings, capacitance layer for voltageindication) can be supplied on request.The program also includes cast-resin insu-lated-bushing current transformers andoutdoor current and voltage transformers.

Fig. 143: Ratings for current and voltage transformers

Fig. 141: Block current transformer type 4MA

Fig. 142: Outdoor voltage transformer type 4MS4

Medium-Voltage DevicesType 4M

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Medium Voltage Devices _ Range Products