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Low
Voltage Motor Start Reactor Choke
For
motors with heavy starting current – 20 hp to 300
hp
Hitech
Systems one of the leading manufacturers of Control panels,
Switch boards and Transformers have developed the EmfCS
– Smooth Starters especially for on load pumps and
motors with heavy starting current.
The
basic principle of EmfCS – Electromotive Force Control
System can be simply described as follows.
Generating counter emf to the supply voltage.
Producing current, which opposes the inrush high starting
current – 6 times of full load current.
In this system the high starting current will be totally
controlled and the motor will be very smoothly started.
The initial starting current will be as low as 20 to 25
% and slowly rise to normal full load current till the
motor reaches its full speed. The EmfCS will return to
normal DOL mode after the motor reaches its full speed,
normally this will be attained with in 7 to 10 seconds
based on the motor load characteristics and the prevailing
load condition.
Based on our experience of more than fifteen years in
the field of transformer and control panel manufacturing
the EmfCS is designed and developed to withstand the
tough load condition, fluctuation in supply voltage
and abnormal load currents.
The
EmfCS smooth starter is designed with transformer iron
core material to give a perfect solution for smooth starting.
Basically
iron core has a higher permeability figure than air core,
which means that it will concentrate the magnetic lines
of force and therefore increase inductance.
The
reactor choke in series with the motor winding gives a
linear increase of starting current by generating counter
emf which limits or chokes the flow of actual current.
The
EmfCS – Reactor CRNO iron core choke is perfectly
designed to perform an inductor’s behavior. With
low frequency [50 Hz, AC system] the EmfCS reactor will
produce the required value of inductance and therefore
counter emf to limit the flow of high starting current.
The
EmfCS reactor acts as an inductor/choke in series with
the motor winding.
When current flows through the reactor a back emf is produced
and the reactor will oppose the fast change of current
flow. This in turn reduces the line voltage and the high
starting current. The motor gently accelerates to its
full speed as the voltage gradually increases to the line
voltage.
When
motor attains its full speed the EmfCS reactor is bypassed
and the motor will continue to run with normal line voltage.
Normally
this will take 7 – 10 seconds based on the motor
load characteristics and the prevailing site conditions.
The
EmfCS – reactor is designed to withstand high starting
current surges and line voltage fluctuations. Super enameled
F-class insulated copper winding wires/strips are used
to give the best heat resistance and insulation between
layers.
Some
reactors available in the market are wound with ordinary
PVC insulted flexible copper cables that are not at all
recommended for winding transformers. Their heat resistant,
strength of insulation and current carrying capacity are
very poor when compared to F class super enameled insulated
copper wires.
The
entire system will be housed in freestanding cubicle sheet
metal enclosure made out of 16/14 SWG CRCA sheet steel
with a standard 10 SWG plinth of
100 mm height. Surface finish of the enclosure will be
siemens grey powder coated.
Normally
our starters are designed to give trouble free performance.
Our technicians will assist during the time of installation
and commissioning. But even if any defect occurs due to
wrong operation of the field operators or by not following
the procedures or any failure of electrical components
our technical staff will be available round the clock
to attend the problem.
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