MODELING AND OPERATION OF CENTRIFUGAL CASTING MACHINES FOR DUCTILE CAST IRON PIPES

Document Type : Scientific and technological

Author

El Nasr Casting Company, Egypt

Abstract

Centrifugal casting machines are a production machines used to produce ductile cast iron pipes in the casting method in El Nasr Casting Company. The Casting Machines were manu-factured by Thyssen Rheinstahl Technik GmbH [1]. They are driven by separately excited DC motor of a nominal voltage of 400V and nominal power 222 kW.  Lower overall efficiency leads to higher electricity consumption. A brief background on the centrifugal casting process is presented along with typical casting machine electrical drive performance requirements. Motor performance characteristics and control strategies are described for both AC and DC machines. A case study is presented, where simulated measurements were performed on Centrifugal casting machine driven by a DC motor (222 kw) and replaced by AC motor (315 kw). Electrical energy, demand, and cost savings are analyzed.
The paper illustrates the difficulties that have been encountered of using DC drives, and presents a study of utilizing AC motor with its variable speed drive. The results indicate the simulated process performance in case of using AC motor.
The centrifugal casting machine driven by a AC motor requires less power to operate than the DC drive. On the average AC drive approximately draws 250 A and 60 kw, while the DC drive approximately draws 350 A and 64 kw. The final results are Electrical energy savings 7% and cost savings 10126 LE/yr for one machine

References

1- Thyssen Rheinstahl Technik GmbH Documentations, DUSSELDROF/ GERMANY- El Nasr Casting Company, Egypt.
2- Modern Control Systems, 11th ed, 2008, Richard C. Dorf & Robert H. Bishop
3- Differential Equations (part 1): First-Order Differential Equations by Evan Dummit, 2012, v. 1.12
4- Ricardo A. Sfeir, P.E. "MEASURED SAVINGS OF DC TO AC DRIVE  RETROFIT IN PLASTIC EXTRUSSION" Proceedings from the Thirtieth Industrial Energy Technology Conference, New Orleans, LA, May 6-9, 2008., ESL-IE-08-05-47
 

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