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Specification
CONSTRUCTION STYLE:
Two-tier modularised contraction for convenience and better serviceability.
- The timing and other intricate electronic sections are housed
in a 19" Euro-chassis having plug-in Euro card for power
supply. Timer and Heat control. The total box can be disconnected
with the help of a single plug. This system could be fixed on
the side of the machine or on top of an independent cabinet as
per the customer's choice.
- One sub-assembly carrying power thyristors and accessories mounted
on chassis could be fitted inside the machine frame or inside
the independent cabinet.
The interconnections between the thyristor panel and the timing
section are done through plug-socket arrangement.
CHARACTERISTICS :
Digital counters built by using C-MOS ICs produce error-free fully
synchronous control of the weld parameters.
CONTROL MODELS :
- ME-201 : Synchronous Control having timing sequence. Heat control
and power thyristors with protective device.
- ME-202 : Synchronous Control having timing sequence. Heat control
and power thyristors with protective device and with forge-delay
facility.
- ME-203 : Synchronous Control having timing sequence with pulsation
facility. Heat control and power thyristors with protective device.
SQUEEZE TIME :
1-99 Cycles ± Zero Cycle in step of 1 cycle.
WELD TIME :
1-99 Cycles ± Zero Cycle in step of 1 cycle (for pulsation
1-9 Cycles HEAT. 1-9 Cycles COOL, 1-9 Number of PULSES).
HOLD TIME :
1-99 Cycles ± Zero Cycle in step of 1 cycle.
OFF TIME :
1-99 Cycles ± Zero Cycle in step of 1 cycle.
FORGE DELAY TIME :
1-99 Cycles ± Zero Cycle in step of 1 cycle.
At the desired point of time with respect to the start of weld
an extra forge force can be applied to the job by energising a solenoid
air valve of air circuit.
SINGLE / REPEAT FACILITY :
This provision enables one weld per initiation or stitch welding
(repeat mode).
HEAT CONTROL UNIT :
This is based on the phase shifted firing of thyristors which enables
smooth and continuous adjustment of welding current from 10% to
100%.
SLOPE CONTROL :
The option to use a "SOFT START" and gradual rise of current
to the selectable maximum (HEAT CONTROL) value of current is useful
to avoid splashes. Upward slope type increase of current during
period of time 1-9 cycles is provided and is adjustable in steps
of one cycle.
POWER THYRISTOR SWITCH ASSEMBLY :
A pair of water-cooled power thyristors of rating suitable for operating
welding machines upto 300 KVA capacity will be provided with the
control. A thermoswitch mounted on the thyristor heat sink inhibits
operation of the equipment if the thyristor gets overheated. Provision
for incorporating water flow switch is available. High volrage surge
suppressing devices are provided to safeguard the power thyristors
from damage due to supply surges.
AUTOMATIC POWER COMPENSATION BY "PHASE
SHIFT" ADJUSTMENTS :
In production set up for the given supply voltage effective value
of current is usually divided by setting the control adjuster to
select a suitable firing angle for the thyristors. However, when
supply voltage fluctuations are experienced, random variations could
cause serious deviations in weld quality. Automatic regulation is
a specially devised electronic technique to modify the firing angle
in accordance with the need for ensuring consistency of the current
(effective value) selected during initial adjustment.
INDICATORS :
Indicators are provided on the front panel which enable to observe
the operation sequence. LED's mounted on printed circuit boards
greatly helps quick and easy location of faults.
Remarks
For specific requirement of additional, different or special features
with respect to electrical or physical aspects, please obtain confirmation
from Mechelonic Engineers.
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