Flexibly Applicable and Communication-Capable

3WL air circuit breakers offer a very flexible applicability and integrated communication capability. They optimally meet the increased requirements placed upon air circuit breakers particularly with regard to the operation and monitoring of network processes in connection with electronic control systems. The quality of this range sets new standards worldwide.

With only three sizes, the 3WL air circuit breakers cover a power range from 630 A to 6300 A. Featuring a 3- or 4-pole design, they are suitable for applications up to 1000 V. All models are characterized by identical design – in fixed-mounted as well as withdrawable version – identical operation and identical comprehensive accessories. The particularity: In the upper performance range, the 3WL is the world’s smallest circuit breaker of its class.

Advantages at a glance

• • Flexible and global applicability for temperatures up to 70 °C; no derating up to 55 °C
• • Easy planning, assembly and retrofitting through modular design with only 3 sizes, few components and uniform accessories
• • Full communication capability via PROFIBUS-DP or Modbus integrated communication concept with 3VL
• • Smallest circuit breaker on the market in the power range from 5000-6300 A
• • RoHS-compliant

Application areas

• • As incoming-feeder, distribution, coupler and outgoing-feeder circuit breaker in electrical systems
• • For the switching and protection of motors, capacitors, generators, transformers, busbars and cables
• • Devices in AC version are available as circuit breaker and non-automatic circuit breaker. Devices in DC version are available as nonautomatic circuit breaker.

International standards and approvals

• • IEC 60947-2
• • DIN VDE 0690 Part 1
• • Climatic withstand capability in acc. with DIN IEC 68 Part 30-2
• • CCC, Gost
• • Shipbuilding, e.g. GL, ABS, LRS, PRS For international applications, also versions in acc. with UL 489 are available. For 3WL air circuit breakers / non-automatic circuit breakers approved in acc. with UL 489 up to 5000 A, refer to catalog LV 16. (Order No. E86060-K1816-A101-A1)

• • The compact design of the SENTRON 3VL circuit-breakers coupled with excellent characteristics fulfills the high demands of today's electrical distribution systems.
• • These circuit-breakers offer a broad product range, improved technology, space savings and easy operation.
• • They are available both in thermal-magnetic (50 A to 1600 A) and in solid-state versions (30 A to 1600 A).

Nowadays we use more commonly Miniature Circuit Breaker or MCB in low voltage electrical network instead of fuse. The MCB has some advantages compared to fuse.
1. It automatically switches off the electrical circuit during abnormal condition of the network means in over load condition as well as faulty condition. The fuse does not sense but Miniature Circuit Breaker does it in more reliable way. MCB is much more sensitive to over current than fuse.
2. Another advantage is, as the switch operating knob comes at its off position during tripping, the faulty zone of the electrical circuit can easily be identified. But in case of fuse, fuse wire should be checked by opening fuse grip or cutout from fuse base, for confirming the blow of fuse wire.
3. Quick restoration of supply can not be possible in case of fuse as because fuses have to be rewirable or replaced for restoring the supply. But in the case of MCB, quick restoration is possible by just switching on operation.
4. Handling MCB is more electrically safe than fuse.
Because of to many advantages of MCB over fuse units, in modern low voltage electrical network, Miniature Circuit Breaker is mostly used instead of backdated fuse unit. Only one disadvantage of MCB over fuse is that this system is more costlier than fuse unit system.

Miniature Circuit Breaker Working Principle
There are two arrangement of operation of miniature circuit breaker. One due to thermal effect of over current and other due to electromagnetic effect of over current. The thermal operation of miniature circuit breaker is achieved with a bimetallic strip whenever continuous over current flows through MCB, the bimetallic strip is heated and deflects by bending. This deflection of bimetallic strip releases mechanical latch. As this mechanical latch is attached with operating mechanism, it causes to open the miniature circuit breaker contacts. But during short circuit condition, sudden rising of electric current, causes electromechanical displacement of plunger associated with tripping coil or solenoid of MCB. The plunger strikes the trip lever causing immediate release of latch mechanism consequently open the circuit breaker contacts. This was a simple explanation of miniature circuit breaker working principle.

Miniature Circuit Breaker Construction
Miniature circuit breaker construction is very simple, robust and maintenance free. Generally an MCB is not repaired or maintained, it just replaced by new one when required. A miniature circuit breaker has normally three main constructional parts. These are:

Frame of Miniature Circuit Breaker
The Frame of Miniature Circuit Breaker is a molded case. This is a rigid, strong, insulated housing in which the other components are mounted. Operating Mechanism of Miniature Circuit Breaker

The Operating Mechanism of Miniature Circuit Breaker provides the means of manual opening and closing operation of miniature circuit breaker. It has three-positions “ON,” “OFF,” and “TRIPPED”. The external switching latch can be in the “TRIPPED” position, if the MCB is tripped due to over-current. When manually switch off the MCB, the switching latch will be in “OFF” position. In close condition of MCB, the switch is positioned at “ON”. By observing the positions of the switching latch one can determine the condition of MCB whether it is closed, tripped or manually switched off.

Trip Unit of Miniature Circuit Breaker The Trip Unit is the main part, responsible for proper working of miniature circuit breaker. Two main types of trip mechanism are provided in MCB. A bimetal provides protection against over load current and an electromagnet provides protection against short-circuit current. miniature circuit breaker working principle There are three mechanisms provided in a single miniature circuit breaker to make it switched off. If we carefully observe the picture beside, we will find there are mainly one bi – metallic strip, one trip coil and one hand operated on – off lever. Electric current carrying path of a miniature circuit breaker shown in the picture is like follows. First left hand side power terminal – then bimetallic strip – then current coil or trip coil – then moving contact – then fixed contact and – lastly right had side power terminal. All are arranged in series.

Miniature Circuit Breaker

If circuit is overloaded for long time, the bi – metallic strip becomes over heated and deformed. This deformation of bi metallic strip causes, displacement of latch point. The moving contact of the MCB is so arranged by means of spring pressure, with this latch point, that a little displacement of latch causes, release of spring and makes the moving contact to move for opening the MCB. The current coil or trip coil is placed such a manner, that during short circuit fault the mmf of that coil causes its plunger to hit the same latch point and make the latch to be displaced. Hence the MCB will open in same manner. Again when operating lever of the miniature circuit breaker is operated by hand, that means when we make the MCB at off position manually, the same latch point is displaced as a result moving contact separated from fixed contact in same manner. So, whatever may be the operating mechanism, that means, may be due to deformation of bi – metallic strip , due to increased mmf of trip coil or may due to manual operation, actually the same latch point is displaced and same deformed spring is released, which ultimately responsible for movement of the moving contact. When the the moving contact separated from fixed contact, there may be a high chance of arc. This arc then goes up through the arc runner and enters into arc splitters and is finally quenched. When we switch on an MCB, we actually reset the displaced operating latch to its previous on position and make the MCB ready for another switch off or trip operation.

Power Contactors for Switching Motors
The Right Power Contactor for Every Application

With a wide range of power contactors for switching motors, we can cover many different applications - up to 250 kW. In sizes S00 to S12, in addition to 3-pole standard contactors, there are also vacuum contactors, coupling relays for optimal interfacing with the outputs of controllers, and various different 4-pole power relays and miniature contactors for the performance range up to 4 kW. The new 3RT2 contactors in sizes S00 and S0 are particularly flexible.
Apart from screw-type connections, the devices are also available throughout with spring-loaded and ring cable lug connections. The auxiliary switches for S00 and S0 can be installed for any sizes. A UC version can be controlled using either AC or DC voltage and simultaneously features much lower power consumption of the coils. Two auxiliary switches are already integrated in the contactors of size S0 which offer even higher contact reliability.
A special highlight: Contactors in size S00 or S0 can be used to configure reversing or star-delta (wye-delta) starters simply by plugging in function modules. These can also be equipped with an AS-i or IO-Link interface as an option, which significantly reduces the control circuit wiring.
As regards safety engineering, contactors of the 3RT2 series also offer some new features: Using the Safety connector, safety related solutions can be configured to PLe according to ISO13949-1 or SIL3 according to IEC62061 – simply plug the Safety connector into the contactors and a redundant contactor assembly is wired up already.

Commercial Status	Commercialised
Range of product	EasyPact MVS
Circuit breaker name  Device short name  Circuit breaker application	MVS08N  MVS08N  Standard
Poles description	3P
Protected poles description	3P 3d
Network type	AC
Breaking capacity code	N - 50 kA
Suitability for isolation	Yes conforming to IEC 60947-2
Utilisation category	Category B
Trip unit name	ETA2I
Trip unit technology	Micro-processor based
Trip unit rating	800 A (-5...70 °C)
Complementary Network frequency	50/60 Hz
Control type	Manually operated
Mounting mode	Drawout
Mounting support	Base plate Rail
Connection position	Horizontal Vertical
Location of connection	Rear
[In] rated current	800 A (40 °C)
[Ui] rated insulation voltage	1000 V AC 50/60 Hz conforming to IEC 60947-2
[Uimp] rated impulse withstand voltage	12 kV conforming to IEC 60947-2
[Ue] rated operational voltage	690 V AC 50/60 Hz conforming to IEC 60947-2
Circuit breaker CT rating	800 A
Breaking capacity	50 kA (Icu) at 220...440 V AC 50/60 Hz conforming to IEC 60947-2
[Ics] rated service breaking capacity	50 kA (Ics) at 220...440 V AC 50/60 Hz conforming to IEC 60947-2
Mechanical durability	10000 cycles (without maintenance) conforming to IEC 60947-2 20000 cycles (with maintenance) conforming to IEC 60947-2
Electrical durability	4000 cycles (without maintenance), category B at 690 V AC 50/60 Hz, conforming to IEC 60947-2 6000 cycles (without maintenance), category B at 440 V AC 50/60 Hz, conforming to IEC 60947-2
Connection pitch	115 mm (without spreader)
Contact position indicator	Yes
[Icm] rated short-circuit making capacity	105 kA (Icm) at 220...440 V AC 50/60 Hz conforming to IEC 60947-2
[Icw] rated short-time withstand current	25 kA (3 s) at 440/690 V AC 50/60 Hz conforming to IEC 60947-2 42 kA (1 s) at 690 V AC 50/60 Hz conforming to IEC 60947-2 50 kA (1 s) at 220...440 V AC 50/60 Hz conforming to IEC 60947-2
Trip unit protection functions	LI
Protection type	Instantaneous short-circuit protection Overload protection (long time)
Fault indication	Overload - Short-circuit - Internal fault
Long time pick-up adjstment type Ir	Adjustable 9 settings
Long time pick-up adjustment range	0.4...1 x In
Long time delay adjustment type	Adjustable 9 settings
[tr] long-time delay adjustment	0.5...24 s (6 x Ir)
Thermal memory	20 minutes before and after tripping
Instantaneous pick-up adjustment type Ii	Adjustable 9 settings
Instantaneous pick-up adjustment range	1.5...10 x Ir
Zone selective interlocking ZSI	With
Display type	Digital display
Type of measurement	Current
Current sensor rating range	400/2000 A
Maximum breaking time  Closing response time	25 ms   < 70 ms
Height  Width  Depth  Product weight	439 mm  441 mm  395 mm  70 kg
Environment Standards	IEC 60947-2
Product certifications	CCC - GOST - IEC - CCS
IP degree of protection	IP40
Pollution degree	4 conforming to IEC 60664-1
Ambient air temperature for operation -	5...70 °C
Ambient air temperature for storage	-25...85 °C (with control unit) -40...85 °C (without control unit)
Contractual warranty Period	18 months