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Sigma MCBs are such devices that protect their connected circuits against short circuit and overload.
Sigma MCBs produced as 3 kA, 4.5 kA, 6 kA, 10 kA and
16kA according to the EN 60898-1, EN 60947-2 and VDE 0660.
They are also conforming to the Low Voltage Directive (LVD) 73/23/EEC.
Up to 25 mm2
cable can be connected to the sigma MCBs, which are designed
to be easily mounted on to the 35 mm DIN rail according to EN 50022.
connection with collective MCB Bus bar is possible.
Maximum torque applied
for connection screws is 2 Nm.
Although Sigma MCBs have availability to make energy entrance from both
upper side and under side, it is recommended to make from upper side.
Connection Terminals own IP20 protection degree according to the EN60529.
All MCBs are designed for safe to touch and easy to seal.
Selection For MCB Tripping Characteristics
- Type B characteristics are suitable for moderately inductive loads having
little or no switching surges i.e. electric heating, water heating, ovens etc.
- Type C characteristics MCBs can be used in general applications such as
ring/radial socket outlets and small motors.
- Installations where the equipment is likely to produce abnormally high inrush
currents, such as transformers, welding machines or induction motors are suited to
type D characteristic.
Protection Of The DC Circuits
The thermal characteristics for Sigma MCBs are unaffected by the type of
current applied, that is either direct current or alternating current. The
magnetic trip value increases by 40%.
For example, in the case of a breaker of
tripping characteristics B and 10A rated current, its magnetic tripping value will be between 30A and 50A in alternating current. The magnetic tripping
value for the same breaker in direct current will be between 42.4A
For DC service, the MCBs full rated breaking capacity can be achieved without
any reduction in performance by connecting protected poles in series.
For values up to 48V=1 protected pole can be used unpaired of the breaking
capacity value. Between 48 and 110V=2 protected poles series connected
can be used without reduction in the breaking capacity. Between 110 and 150V=, 3
protected poles series connected must be used, and 4 poles up to 200V=
Influence Of Non-Standard Frequencies
For operational frequencies greater than 50/60Hz, the effect of these
non-standard frequencies must be taken into consideration. Thermal characteristics are independent from variation in frequency. Magnetic tripping values are
directly affected by frequency. As a reference, for frequencies of 100, 200,
300 and 400Hz, the values at which the magnetic tripping occurs become increased
in a 10, 20, 30 and 40% respectively.
Sigma MCBs have been designed to lose minimum power in their connected
circuits and their power loss per pole is much less than the value stated
in EN 60898-1 standards.
Protection Of Motors
The protection of motors against the effects of an internal short circuit
must be ensured, allowing at the same time the overcurrents (starting) without causing tripping of the protection element.
TThis element must also ensure protection of the line, of the contactor and of
the thermal relay associated to the motor.
Protection Of The Lighting Circuits
When choosing the MBCs for protection of lighting circuits, it should be
considered the power of the lamp, kind of the lamp, number of lamps and high
peak currents when the lamps are energized.
In the lighting circuits consisted of Sodium and Mercury vapor discharge
lamps,the peak currents may occur up to 25 times of the rated current at the first
3 ms. Following this, 7 times of the rated current may be drawn within 2
In the lighting circuits,inwhich there is electronic ballast worked with high
frequency ,the peak currents may occur up to 25 times of the rated current at
the first 250 - 300 μs.
For these reasons, the MCBs are to be selected according to the type of lamps
and their endurance against peak currents, so generally C type MCBs are
used in the lighting circuits.
But because of the cable resistance between the lamp and MCB, The value of peak
current is limited to an inferior value depending on the distance.
It is possible to make tripping and signaling remotely to the Sigma 6 kA and 10
kA MCBs by adding shunt trip and fault signal contact.
Fault signal contact are mounted to the left side of the surface of the MCBs or
Shunt Trip and when the MCBs are tripped because of the overload or short circuit, the
contacts change the position however when the MCBs open or close the circuit by
manually, the contacts do not change the position.
УЗО, диф. реле и автоматы серии SIGMA.
Автоматические выключатели серии ABL.