|
Specifications
Standard Rating:
150, 200, 250 KVA (Higher capacities available on request).
Type of Machine FH - Series:
Automatic and semi-automatic high-speed flash Butt Welding Machine
with hydraulically operated clamping and upsetting mechanism.
Construction:
Main frame assembly is of sturdy, all-welded steel plate fabrication
suitably braced and stiffened at points of stress to minimise deflection
and thermally stress-relieved; the transformer placed separately
from the main frame and connected through flexible connectors. Left
hand platen is fixed and right-hand platen is movable and guided
on precision - hardened and ground slides with provision for wear
adjustment.
Welding Transformer:
Transformer is of special type conforming to IS: 4804 Part I - 1968
and TWMA Standards. Water cooled, having core of high grade electrical
steel, primary and secondary coils of solid electrolytic copper
of ample section, heavy duty class 'F' insulated and encapsulated
and suitable for withstanding severe loading conditions. Thermostatic
protection has been provided against overheating of the transformer.
In case of overheating, the control circuit opens, thereby preventing
its operation till normal condition is attained.
Current Control By Transformer Taps:
Transformer primary coil provided with taps brought out to tap changing
links for adjustment of welding current in 4 steps from 50% to 100%.
Tap change links are enclosed behind the machine panel.
Cooling System:
Transformer, secondary bus bars and electrodes and thyristors are
water-cooled. Internal water-cooling piping is provided in the machine.
All circuits terminate into a single outlet.
Water Flow Switch: (Optional accessory at
extra cost).
Water Flow Switch shall be provided with machine to ensure adequate
flow of water while operating the machine. When sufficient flow
of water is not provided the control circuit trips off and machine
stops. Visual indication shall also be provided to indicate inadequate
flow of water.
Clamping & Tooling:
Clamping pressure applied by individual hydraulic cylinder through
either alligator-type lever operated clamps or vertical clamp slides
depending on job configuration.
Upper and lower tooling fitted with one set of replaceable electrodes
/ dies to suit particular geometry of the components.
Pre-Heat, Flashing & Upsetting:
A movement of right-hand platen is effected by a direct acting hydraulic
cylinder. Provision is made for automatic pre-heating of the work
pieces prior to the commencement of the flashing operation. The
retractable cylinder facilitates only a small stroke of the cylinder
to be operational during this period. The ON and OFF timing periods
of pre-heating are separately controlled by precision electronic
timer having a range of 2-250 cycles continuously adjustable. The
numbers of pre-heat cycles are selected from 0-99 impulses in steps
of one impulse.
Flashing parameters such as the initial speed, rate of acceleration
and final speed are under the control of a flow control valve. This
valve determines the initial speed of flashing and acceleration
and final speed achieved by the moving platen at the pre-set distance.
Upsetting is achieved by bypassing the flow control valve and dumping
the oil suddenly. Upsetting pressure can be varied by means of pressure
regulating valve. Cutting off the current just after the application
of the upset force is controlled by precision electronic timer.
Welding current interrupted automatically after pre-adjusted interval
starting from the moment of upsetting by an Electronic timer unit
adjustable to suit any welding requirement.
Post-Heat:
(Optional at extra cost). A post-heat timer and a programmable 6-second
downslope control of absolute accuracy enabling excellent post-weld
heat treatment to the weld heat treatment to the weld joint can
be provided at extra cost.
Contractor:
Heavy-duty Thyristor Contractor incorporated in the primary circuit
for on/off switching of the set.
Main power contractor is chosen as per the requirement of the welding
machine. Two high Power thyristors on a water-cooled heat sink are
connected in anti-parallel. The gates of the thyristors are connected
to the firing circuit, which triggers the firing signals to the
thyristors. The thyristors are protected from voltage and current
surges by conservative designs. A thermo switch mounted on the water-cooled
heat sink offers additional safety to the Thyristors.
Servo Control:
(Optional at extra cost). Control functions such as Pre-heat, Flashing,
Upsetting and Post Heat, which are done with Non-synchronous timers
and relay logic is replaced with a compact PLC with appropriate
programming.
The right hand side platen movement is controlled by means of a
Servo Valve having position feed back (with the help of Linear Transducer)
and current feedback for proper flashing and upsetting. Pressure
feed back is also applied to the Servo system during pre-heating
for fast and controlled heating. Flashing parameters such as initial
speed, rate of acceleration, flashing speed, etc. are controlled
with the help of servo valve to get optimum results.
Hydraulic Power Pack:
The hydraulic power pack is an integral unit, consisting of a tank,
strainer, pumping unit, heat exchanger and the group of valves and
devices as per the circuit of the system arranged for easy servicing.
Only the hoses are to be connected to the bulk heads provided for
starting up the hydraulic system. It is powered by a 3-Phase Induction
Motor.
Service Requirements
Supply Voltage:
415 Volts, Single Phase, 50 Hz. (2 lines of 3-phase supply) for
transformer. 415 Volts, 3-Phase. 50 cycles, for hydraulic power
pack as given in technical specification.
Main Supply Disconnect Switch:
To be provided by customer. 2-Pole, Isolating Switch Unit (rating
as recommended).
And
3-Pole, Isolating Switch Unit (rating as recommended).
Mains Supply Cable:
To be provided by customer, 2-Core, copper/aluminium conductor (rating
as recommended).
And
3-Core, Copper / aluminium conductor (rating as recommended).
Water:
Customer to provide water supply of recommended flow rate, free
from residue forming impurities and at a temperature less than 30oC.
|
