Power switches
ACBs are a specific type of electrical breaker. They are intended
especially for industrial applications, because it is thanks to them
that the electrical network can work without any problems. Power
switches are used where very high power is turned off. As a result, they
protect against overloads and short circuits of devices in the same
circuit. Circuit breakers of this type can also be used to control power
distribution in a network.
Power switches:
characteristic
The construction and operation of devices whose main role is
protection of electrical devices always depends on the intended use
of a particular circuit breaker. Therefore, three main types of ACB can
be distinguished. They are:
- low-voltage circuit-breakers up to 1000 V, using the arc
breaking mechanism to quench the arc and trip the circuit breaker,
- medium voltage power circuit-breakers (also called vacuum
circuit-breakers), which trip on decay of the arc, whereby the pairs
of materials from which the contacts are made to break the circuit
are lost
- high-voltage power circuit-breakers, up to 500 kV, which are complex
designs with many technological changes.
The general principle of operation of ACBs is based on the fact that in
the connected circuit, the current leads to the formation of an electric
arc, and the activation of the switch is related to the extinction of
the arc current. The arc extinction mechanisms are different. Power
switches are professional devices that minimize the negative effects of
overload or short-circuits .
The selection of a circuit breaker to protect specific electrical
devices is made on the basis of data obtained about the voltage and
rated current of the connected equipment. It is important to sum up all
values for a specific circuit. The power switches available on the
market have a large power range and impressive adjustment possibilities,
so simply comparing the motor power with the power switch rated current
is not enough. When choosing low-voltage circuit-breakers, you need to
know the inrush currents. Also, care must be taken that the ACB is not
one safety device in a particular system.
Power switches: overcurrent detection
Power switches protecting electrical equipment against overloads or
short circuits also control the power flow in the network. They are
perfect for switching stations and high-voltage systems, where
protection of electrical devices is necessary. The low-voltage power
circuit breakers available on the market are distinguished by high load
capacity and low energy dissipation. In addition, the ACBs operate
without problems at high ambient temperatures. Professional devices used
industrially detect overloads such as:
- overloads identified by thermal trigger,
- short circuits recognizable by an electromagnetic release,
- overloads and short circuits, which are detected by an electronic
trip unit.
Thermal and electromagnetic releases are usually combined in
thermal-magnetic circuit breakers, with limited possibilities to change
parameter settings, compared to electronic releases.
The selection of individual switches is made taking into account
parameters such as: short-circuit capacity, number of modules or rated
voltage. Modern electrical devices guarantee the creation of an
insulation gap in the electrical circuit or a circuit break in the event
of an overload or short circuit. Each circuit breaker, as a so-called
short-circuit switch, is suitable for loads that exceed 10 times the
rated current. Therefore, it is used to disconnect short circuits in an
electrical circuit. By deciding to purchase a specific device with
optimal parameters, you get a guarantee that it will work perfectly in
industrial conditions. Especially when the equipment supplier is a
proven manufacturer.
