Variable-speed drive system for high pressure grinding rolls

• Lower ore grades
• Increased material processing to achieve business objectives
• Potential increase in CAPEX
• Need for reliable, maximum throughput and robust grinding solutions
• Remote locations
• Extreme environmental conditions (high altitude, temperature variation)

 

 

Our state-of-the-art HPGR drive technology for use in comminution is a variable-speed drive system.
Decades of engineering expertise translates to an optimized drive solution specially engineered to fit your specific site and HPGR requirements.

Standard system components
While the complete system is tailored based on your specifications, the following components are typically part of the standard package: Converter (voltage source inverter topology), transformer and motor

When evaluating whether to go with a medium or low voltage system, our engineering experts not only consider the HPGR motor power, but also how to optimize cost without compromising performance and reliability. Your power supply and control center options. We offer two options for power supply and control center design: Integrate the power, control and ancillaries into your existing E-rooms, or choose a self-contained, pre-commissioned solution.

Optional system services
- Torsional analysis of total drive train to validate design.
- System commissioning by dedicated application experts to ensure flawless operation.

HPGR drive system with RollXtend™ technology
The drive system with RollXtend technology provides accurate control of torque (load) and speed.
An HPGR with a brand new set of rollers starts operation with identical torque and speed. Over time and based on various operating factors (e.g. ore characteristics, operating pressure, feed etc.), the rollers experience different wear rates. With RollXtend the load provided by both rollers can be fine tuned by the operator based on the wear rate measured.

To leverage the benefits of using HPGRs in comminution and reach optimal productivity, a reliable and flexible drive system is a must. With its advanced smart operation and protection features, our drive system ensures optimal productivity, operational efficiency and increased roller life for your grinding operations: 

1. RollXtend™: provides full flexibility to vary the torque delivered by each roller, while maintaining identical circumferential speed


2. Maintenance mode: roller creeping for inspection and maintenance activities is achieved with our dedicated maintenance mode function combined with the easy-to-use drive system HMI, eliminating the need for an auxiliary drive


3. Upstream breaker management: the drive system controls the upstream medium voltage breaker, guaranteeing co-ordination with the total system operation, ensuring operator and equipment safety.


4. To further enhance HPGR productivity we also offer optional drive system components and features such as specially engineered motors, vibration monitoring and a surge protection feature.
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Cost benefits

• Maximized total roller life due to equal roller wear with RollXtend technology
• CAPEX and OPEX savings (time lost in engaging and dis-engaging auxiliary drive), as need for auxiliary drive is eliminated for maintenance operations

Operator and equipment safety benefits

• Increased operator safety with maintenance mode. Inspection and maintenance activities can be performed without auxiliary drive
• Converter control of upstream circuit breakers avoids equipment damage resulting from transformer in-rush currents
• Coupling supervision - monitors deviations in torque. In case of a coupling failure, the drive detects it and trips
• Stand still detection (optional) - to protect mechanical and electrical drive system components, the motors should not restart if the rolls are still turning after a stop command. This function detects if the rolls are standing still and then releases the start command for the operator.​
• Over-duty cycle mode (optional) - permits additional torque for a certain amount of time to overcome overload situations (e. g. improper feed rates), allowing operators to implement corrections and avoid machine stoppage.

Electrical benefits

• Network friendly operation
• Current and voltage harmonic within IEEE 519 limits eliminates need for additional filtering equipment.

Process and operational benefits

• Instant roller reaction to change in ore characteristics and hopper feed rate by setting of appropriate speed
• Quick reaction to frequent load changes (e.g. irregular feed size) possible with direct torque control (DTC) used in convertor
• Lower pressure spikes and reduced stud breakage due to maintained small zero and operating gap

Mechanical benefits

• Reduced mechanical stress on gearbox and reduced roller damage due to smooth starts at high torque
• Fatigue failure protection of drive train and gearbox via torque limits in the drive
• Prevention of high intensity vibration caused by variations in feed due to use of variable speed drive