On Land Belt Conveyor

Ambuja Cement Ltd (Now part of Adani Group) is among the leading cement companies in India. It is a member of the Adani Group - the largest and fastest-growing portfolio of diversified sustainable businesses. Ambuja Cement is known for its hassle-free, home-building solutions.

An established brand in India, Ambuja Cement is known for its high strength, high performance Ordinary Portland Cement (OPC) and Pozzolana Portland Cement (PPC). OPC & PPC both are high quality active hydraulic binders & are preferred brands in the market for all the construction applications. The company currently has a manufacturing capacity of 29.65 million tonnes.

In a significant breakthrough for the material handling industry, a recent project in Ambuja Cement witnessed the successful replacement of five Competitor-A Model AxS8xx Variable Frequency Drives (VFDs) with a superior solution, designed and implemented by our team. The challenge at hand was the inability of the existing VFDs to initiate the motor when the belt conveyor was loaded with material. Also, the maximum material it can handle was 1300 TPH at 1380 rpm. In response, our innovative VFD not only addressed this limitation but also showcased remarkable improvements in performance and reliability.

The On Land Belt Conveyor (OLBC), spanning an impressive 2.7 kilometers, serves as a crucial component in raw material crushed lime stone transportation for the Cement Plant. The existing AxS8xxx VFDs were struggling to start the motor when the conveyor was laden with material, presenting a significant operational bottleneck. At times, the customer needed to empty the conveyor belt if due to some reason, the VFD belt was stopped with material. One can imagine the situation when someone is assigned with this task when it is critical to run the conveyor immediately. The need for a more robust and efficient solution became evident, prompting our team to develop a VFD tailored to meet the unique demands of this application.

The 2.7 kilometers long conveyor, designed and commissioned by Macmet is a unique in nature as it has a 950 meter downhill at an angle of 17° at the tail-end, and has 1750 meter uphill at an angle of 14.5° at the head-end or motor-end where the material is emptied. The effective lift is 270 meter. The maximum belt capacity is 1600 TPH.

The OLBC uses five 450 kW, 4-pole Induction Motors, four are installed at the head-end whereas one motor is installed at the tail-end.

Apart from the main two challenges of starting the belt with material laden and running the belt at capacity of 1500 TPH, there were other multiple challenges in this applications.

First one is to synchronize all the five motors so that they generate the required torque and at the same time they share equal load. Out of five VFDs, four are in the near vicinity but the fifth one is at the tail-end. So, ensuring the equal sharing is critical.

Second, when the feeding starts, all the VFDs go into regeneration due to the downhill portion of the conveyor at the tail-end. So, sizing of the dynamic braking and ensuring equal sharing of regenerative torque among the five VFDs.

Third, the motors are placed at long distances from the MCC panel, almost 500 meter. Fourth, starting the conveyor belt when the tail-end is empty and all the material is at the head-end.