N LTD, KOTA” is a
govt. of India
in Kota (Raj.) in 196667
It has its plant at
(Kerala) with over 25
years of experience
and a dedicated work
For assembly &testing of hi-tech electronic instrument,
totally dust free air conditional hall are used with static
Rajasthan electronics & Instruments ltd. (REIL) Jaipur is a
subsidiary of IL and is manufacturing & supplying non
conventional energy devices and electronic energy meters.
The products manufactured at IL are accredited with ISO
9000 series quality system certification.
IL has supplied over 3000 units of mini UPS ranging from
1kva to 150 kva.
It has supplied instruments on turn key basis for 2 thermal
power stations in Malaysia & established a service center at
Kufa complex in Iraq.
I have visited following sections during my training period
that are:Railways Signaling Relay department
Card Assembly (PCB centre)
UPS (Engineering, Production, Servicing) centre
A relay is an electrical device that opens or closes several
circuits in response to a current in another circuit.
By energizing / de-energizing one relay, several other
relay circuits can be controlled by contacts of that relay.
When the relay coil is energized , this creates an
electromagnetic field that attracts the relay armature to
Attached to this armature is a mechanism for either
opening or closing the relay contacts that are electrically
independent from the input voltage to the relay coil.
Most relays have two types of
contacts. One set of contacts are
“made” or closed when the relay is
energized. These are known as
“Front Contacts.” Conversely these
contacts are opened or broken when
the relay is de-energized.
Back contacts of the relay on the
other hand are “made” (closed)
when the relay is de-energized and
broken (open) when the relay is
LINE RELAY: - This type of relay is used for classification
of line. It gives signal to lines for up and down. There are
two signals Red and Green. Here, red signal indicates that
the line is busy whereas the green signal indicates that line
TRACK RELAY: - This type of relay is used for changing
track at railway station. As we know only two lines up and
down are present & number of lines are present at railway
KEYLOCK RELAY: - These are automatic relay & are used
for the protection of accidents when train arrives & the gate
is automatically closed. These all types of relays are
controlled at control room
It is a process of mounting the components
Types Of Card Assembly1.Through Hole
2. Surface Mount Technology
In this process components are mounted through drilled
hole on the PCB.
In this wave-soldering machine is used for Soldering
Through Hole components
The process consisting of 4 sub process
2. Pre heating
3. Wave soldering
4. Rework &touch up
Wave soldering is a large-scale
soldering process by which
electronic components are
soldered to a printed circuit board
(PCB) to form an electronic
The name is derived from the use
of waves of molten solder to attach
metal components to the PCB.
The process uses a tank to hold a
quantity of molten solder; the
components are inserted into or
placed on the PCB .
The process is much faster and can
create a higher quality product than
manual soldering of components.
Surface mount technology (SMT) IS AN
ELECTRONICS ASSEMBLY TECHNIQUE where
Electronic components are mounted to the surface
of printed circuit board without holes drilled
through the board for insertion of component leads
This method is a very efficient and fast technology.
It saves the cost of placing the component &time
about 30% more faster than the work power.
Surface mount assembly is basically a four-step
process:1.Print the solder paste/ glue.
2.Place the components.
3.Reflow the paste to form the solder
interconnection between the component and the
land area of the board.
1.Screen Printer- To print the solder paste / glue on the
board .The places on the pcb where we want to fix the
component is made shining by putting this paste.
We develop a program showing which component it’s
Here the components are picked up and placed at
There are different nozzles as per the component.
They create a vacuum ,pick up the component and place
them on the PCB.
Components are fed through three methods reel , tray &
It’s speed of placing is 20,000 components per hour.