हैलो दोस्त
आपका हमारे इलेक्ट्रिकल चैनल atozelectricalinformation में स्वागत है
हमारे इलेक्ट्रिकल चैनल में इलेक्ट्रिकल से संबंधित प्रैक्टिकल और इलेक्ट्रिकल थ्योरी वीडियो बनाया
जाता है ..
Hello dost
welcome to our electrical channel atozelectricalinformation..
Made practical and electrical theory videos related to electrical in our electrical channel goes ..
Digital RCD/GFCI/ELCB/RCC Tester WORK...
For correct application of residual current devices (RCDs) it is
necessary to know the principle of function and basic rules of
their application. The actual principle of differential protection
was described as early as in 1928 as a solution for protection
in case of contact with high voltage. First actually functioning
residual current devices for use in low-voltage installations were
designed in 1940s with focus on protection in the event of insulation failure. Their sensitivity was around 100 mA and in 1950s
it could be raised up to around 30 mA, which was already sufficient to prevent a fatal injury of persons in contact with live parts.
Installations fitted with residual current devices started to face
problems with unwanted tripping due to surge voltage during
storms. A solution was presented by Dr. Gottfried Biegelmeier,
who had a residual current device patented with an accumulator
patented in 1957. It utilized a delaying circuit with postponed tripping by at least 10 ms, sufficient for all surge voltage in the network to subside (type G; from German das Gewitter = thunderstorm). This was a solution to unwanted tripping of residual current devices during thunderstorms. All nowadays applied delayed types (G, S) utilize this principle.
In 1960s, protection with sensitive residual current devices,
providing protection even in case of direct contact with live
parts, started to become widely applied. At first, they stated to
be applied in bathrooms, outdoor installations and agriculture,
and later become mandatory for all installation with layman’s
operation. This measure demonstrably reduced the number of
fatal injuries in low-voltage installations. At present, residual
current devices are applied in all low-voltage installations
Types and characteristics of residual current devices (RCDs)
Every residual current device (RCD) has three basic components
- summation current transformer, trip relay and switching
mechanism. The function of the various parts is to detect and
to evaluate the residual current and to interrupt the power supply if the residual current exceeds a certain value. For correct
function of an RCD, all live conductors of protected circuit, or
at least as many conductors as necessary for correct appliance
function, must pass through the summation transformer.
An RCD works on the principle of comparing currents in
live conductors passing through its summation current
transformer. In normal conditions (no phase-to-ground fault),
the sum total or instantaneous current values equals to
zero. Magnetic flow from various working conductors are
induced inside the core of the summation current transformer
and the sum total of their instantaneous values equals to zero
(vectorial sum). Only once earth current flows, a certain part
of the current starts to flow outside the live conductors, which
creates an imbalance condition. This causes excitation of a
corresponding magnetic flow inside the core of the summation
current transformer and the output winding generates current
that will activate the trip relay and gives impulse to tripping the
contacts of the RCD.
Summation current transformer is mostly designed as a
ring-shaped transformer. Permaloy is used as magnetic material; newer types may use special magnetic materials with nanocrystalline structure. The core of a voltage-independent RCD is a
trip relay with permanent magnet (PMR), see Figure 9. In idle
state, the relay armature is constantly held. Once current is conducted into the excitation coil, the attraction force of gravitation
of the permanent magnet is weakened and the spring force will
swing away the relay armature. Owing to its simplicity and proven
reliability, this type of polarized relay is applied most frequently.
The switching mechanism of the RCD must be sensitive and
at the same time provide sufficient force on the contacts. Reliable function must be ensured in all assembly positions. Every load current path must be capable of conducting nominal
Video Highlight
How does a RCD tester work?
What is RCCB and its working principle?
What is the purpose of ELCB tester?
Sew 1812 EL Digital Elcb Tester
2712 EL Digital ELCB (RCD) Tester
SEW 1812 EL B Digital rccb Tester
Electrical safety device
#rcd
#GFCL
#ELCB
#RCCB
#SEW1812EL
#HAVELLSRCCB
#ABBRCCB
#SiemensRCCB
atozelectricalinformation@gmail.com
/ @atozelectricalinforma...
9 сен 2024
