Uncoiler electric drive of electrotinning line 1200/III
Customer: Karaganda Metallurgical Plant JSC “ARCELOR MITTAL TEMIRTAU”
Technological process specification
Electrotining line 1200/III is destined for deposition of tin by electrotinning
way at the surface of steel cold-rolled strip; the final goal is the production of tin (white) sheet for food industry.
Equipment of electrolyte tinning line includes as follows:
- Inlet area
- Chemical area (middle area)
- Outlet area
is meant for uncoiling of black tin coil, welding among themselves,
also for laying in the supply of strip reservoir which is necessary for continuous working of chemical
area during the welding of overlapped strips.
is destined for removing of fat and mechanical pollution from the strip surface,
covering of tin coating, flowing, passivation, strip washing and drying between separate technological operations, electrostatic oiling.
needs for coiling of finished production in coils also for strip reservoir forming, providing chemical
area continuous work during rolling change from one coil to another.
Continuous feed of black tin strip at outlet area provides two uncoilers.
Uncoilers also make tension at the area till the falling roll. Tension reference quantity is set by the operator from the pulpit.
Electric drive and both uncoilers control structure are duplicated.
Due to the fact that it was general automatic control system modernization of the electrolyte tinning
line-1200/III with all drives change, it was decided to change uncoilers drives, thereby modernized control structure.
Requirements to control system
SOLUTION AND AUTOMATION SYSTEM CHARACTERISTICS
- Task calculation at the drive current dased
on required tension, mill roll reference
radius, drive angular rate metal thickness
- The choice of strip tension value within
0…0,5 tonne and tension reference value
maintenance in all uncoiler working modes
with accuracy not worse than 10 per cent;
- Two-zone regulation (with field decay at
more than nominal speed;
- Armature current task calculation for inertia
moment compensation in dynamic modes
and for mechanism and motor mechanical
- Coil radius calculation on signals of
uncoiler rotation velocity and strip line speed;
- Direct value determination of coil radius;
- Speed regulation at the momemt of strip
break and strip break control;
- Reducing of motor excitation current on
required rate at the moment of motor stop;
- Working possibility of the control circuit
with direct and indirect tension regulator;
- Rotation speed regulation in “front
charging” modes, “back charging” mode
with acount of coil radius;
- Strip tension calculation.
Uncoiler electric drive automation is formed on the basis of SIEMENS converter SIMOREG DC MASTER 6RA70
in cabinet-type modification with digital microprocessor control, having small size, high reliability, simple and reliable
diagnostics system of breakdown and failure, completed with additional baseplates for connection «PROFIBUSDP» in digital information-management environment.
Speed modes control system is implemented on the basis of SIEMENS programmable logical controller SIMATIC S7-300 CPU 315-2DP.
Project implementation period
Project implementation period is 5 months, commissioning is November 2007.