The client’s facility in Maharashtra manufactures discs with boron steel. The facility has two steel rolling mills and follows a metal forming process in which metal stock is passed through pairs of rolls to reduce the thickness and keep its thickness/shape uniform. These rolling mills are operated with 250Hp and 350Hp Slip ring motors.

The customer faced with few issues during the operation of these two rolling mills. While starting the Mill, the main breaker was tripping frequently which was affecting the production time. Due to frequent failure of power supply, the client was seeing high operational and maintenance costs.

To address the aforesaid challenges, the customer approached E&A to study the existing system and propose a solution that would help in improving the overall energy efficiency of the rolling mill. A team from the Drives & Automation group conducted audits at the factory and measured the performance of motors and other key parts of the process to identify the biggest potential for energy savings.

It was found that 250Hp and 350Hp Slip ring motors had low-efficiency and were consuming an unnecessarily large amount of electrical energy. The breaker tripping was the result of high current jerk due to the high inertias of rolling mills. Also, the installed LRS (Liquid Resistance Starter) based motor starting system was not convenient owing to high maintenance cost and frequent manual intervention to operate the LRS starters. The team proposed the use of Fx2000 Variable Frequency Drives (VFDs) and replaced LRS starting operation with VFDs. The VFDs provided a frequency-controlled start. The high torque output feature of Fx2000 series drives ensured sufficient torque is developed in the motor even if the rotor resistance starter is removed.

The high torque function of Fx2000 Drive is the most important feature used to start the mill. While providing full torque with Fx2000 VFD, the starting current was restricted within

120%-150% of motor FLC (full load capacity) which in another case with LRS starter was up to 300%.

With Fx2000 Drives, the customer now operates the mill with lower speed and shuts down the mill on non-availability of material, which was not possible with LRS due to starting issue.

The solution enables the plant operators to reliably and efficiently operate the rolling mills and it helped in:

• Achieving Energy Savings up to 40%
• Eliminating of LRS starter thereby reducing overall maintenance
• Major reduction in starting current thereby breaker tripping issue was eliminated
• Improving the mechanical life of the system due to smooth operations

As consumers of electricity, we all need an uninterrupted power supply to continuously run the operations of buildings, industries and other infrastructure. At the same time, we cannot ignore the quality of power which is impacted by the use of switching electronic devices like variable speed drives (VFDs), uninterruptible power supplies (UPS), switched-mode power supplies (SMPS), light-emitting diode (LEDs), etc. The poor quality of power leads to premature failure or degrades the performance of equipment and has a negative impact on the overall electrical system.

E&A’s Power Quality Solution helps run all your electrical systems efficiently and reliably by improving the quality of power in its distribution network.

Consult with the E&A team to know how you can consistently maintain Unity True-Power Factor and mitigate current harmonics as per IEEE 519 or about a special solution for high voltage harmonics.

E&A’s offerings include Type Tested APFC Panel as per IEC 61439 & IEC 61921, a wide range of Active Harmonic Filters, Hybrid Harmonic Filters, and many others.

Every energy unit is charged and it is thus essential to know where it is being used. E&A helps you to measure your energy spend.

Know more about

how our SmartComm EMS

(Energy Management Software) helps you to monitor energy consumption in real-time, take corrective actions in areas of energy wastage and improve energy efficiency.