Case Study: How a Quarry Reduced Downtime by 30% Using ABB ACS880 Drives
Heavy industry operations such as quarries and aggregate plants face constant pressure to keep conveyors, crushers and pumps running reliably. Unplanned downtime can cost thousands of pounds per hour. This case study shows how one UK quarry reduced unplanned downtime by 30% and energy use by 18% after upgrading to ABB ACS880 variable frequency drives (VFDs).
We’ll walk through the initial challenges, the design and implementation process, and the measurable results — plus share tools like our VFD Sizing Calculator and Cable Sizing Calculator to help you plan your own upgrade.
Background: Production Challenges in a Quarry Environment
The quarry’s existing control system relied on ageing direct-on-line starters powering multiple 75 kW conveyors and 45 kW slurry pumps. Operators reported:
- ⛔ Frequent mechanical failures due to hard starting
- ⛔ Motor overheating and trip events
- ⛔ Energy bills exceeding expectations for throughput levels
- ⛔ Limited process control — conveyors ran at fixed speed regardless of load
During peak months, the site lost an average of 12 hours per month to unscheduled maintenance, costing roughly £14,000 in lost production and overtime labour.
Objective
Plant management wanted to achieve the following within one budget year:
- ⚙️ Reduce mechanical stress on conveyors and pumps
- ⚙️ Improve uptime and cut unplanned maintenance
- ⚙️ Lower overall kWh consumption and reactive power penalties
- ⚙️ Gain visibility into motor status and faults
Solution: Deploying ABB ACS880 Drives
ABB’s ACS880 series was selected for its ruggedness, built-in choke for harmonic mitigation, and advanced vector control suitable for high-torque loads. Engineers installed 14 drives ranging from 22 kW to 110 kW across conveyor lines, slurry pumps and crushers.
Key Features Used
- ✔️ Direct torque control (DTC) — instant torque response and better speed regulation
- ✔️ Integrated line choke — reduced harmonics without external filters
- ✔️ IP55 wall-mount enclosures — ideal for dust-laden quarry conditions
- ✔️ Built-in Safe Torque Off (STO) for safety interlocking
- ✔️ Fieldbus communication (Modbus RTU) to link with the PLC
The project team also used ABB’s drive composer software for commissioning, shortening setup time by 40%.
System Design & Sizing
To ensure proper selection, the engineering contractor used our VFD Sizing Calculator to match each drive to the actual full-load current and torque curve of the motor, allowing margin for the quarry’s harsh starting conditions.
For long cable runs between the MCC room and field motors (up to 70 m), engineers verified conductor gauge and voltage drop using the VFD Cable Sizing Calculator. Braking energy on inclined conveyors was dissipated via external resistors sized with the Braking Resistor Calculator.
Installation and Commissioning
The drives were installed in two 48-hour shutdown windows to avoid production losses. Each conveyor and pump drive was configured with soft-start ramps, torque limits, and load-sharing control. The quarry’s maintenance team received training on ABB’s keypad interface and remote diagnostic tools.
Commissioning Checklist
- ✅ Motor data (V, A, Hz, rpm) entered from nameplates
- ✅ Auto-tuning completed on all drives
- ✅ Accel/decel times optimised for belt tension and flow stability
- ✅ Drive fault outputs wired to PLC alarms
- ✅ EMC compliance verified per EN 61800-3
Results After Six Months
| Metric | Before Upgrade | After ABB ACS880 Upgrade |
|---|---|---|
| Unplanned Downtime | 12 h/month | 8 h → 4 h/month (−30%) |
| Energy Consumption | 82 MWh/month | 67 MWh/month (−18%) |
| Maintenance Cost | £3,900/month | £2,400/month (−38%) |
| Payback Period | — | ≈ 13 months |
Operators also reported smoother start-ups and elimination of belt “snatching” on incline conveyors. The plant’s power-factor penalties were reduced by half thanks to improved current waveform.
Performance Feedback from the Site Engineer
“Before the upgrade we were constantly fighting tripped breakers and stretched conveyor belts. The ABB ACS880 drives give us soft torque on every start and easy parameter access. We’ve cut downtime by nearly a third and can monitor every motor’s load live from the control room.”
Energy Efficiency & Power Quality Improvements
The drives’ built-in harmonic choke limited total harmonic distortion (THD) to below 35%, eliminating the need for separate filters. Variable speed control on slurry pumps reduced flow surges and improved process efficiency. With the conveyors running only as fast as production demanded, daily energy use dropped by roughly 15 MWh.
Additional savings came from the drives’ ability to operate in regenerative braking mode on descending conveyors — energy was dissipated safely using resistors sized via the Braking Resistor Calculator.
Integration with Existing Control System
The quarry’s PLC system (Allen Bradley CompactLogix) communicated with the drives using Modbus RTU. Each ACS880 reported current, speed, torque and fault status directly into the SCADA dashboard. Operators could start/stop conveyors individually or in sequence and view load trends across shifts.
To compare, the site previously considered Allen Bradley PowerFlex 755 drives (Allen Bradley VFDs), but the ABB’s integrated choke and outdoor IP55 housing offered simpler installation for dusty environments.
Lessons Learned
- 🔹 Correct drive sizing and motor parameter tuning are critical for torque stability — use the VFD Sizing Calculator.
- 🔹 Proper cable screening and earth bonding prevent nuisance trips — see our Cable Sizing Calculator.
- 🔹 Regular parameter backups reduce recovery time after faults.
- 🔹 Operator training maximises the benefit of new technology.
Extending the Project: Future Expansion
Following the success of Phase 1, the quarry plans to retrofit additional 160 kW crusher drives with ABB ACS880-01-045A-3 units, and install ABB ACS355 drives on auxiliary conveyors for improved coordination with the main system. This mixed configuration allows both cost optimisation and consistent interface across the site.
Environmental and Sustainability Impact
With lower energy use and reduced mechanical wear, the site’s carbon emissions dropped by approximately 35 tonnes CO₂ per year. Lower vibration and fewer mechanical failures also improved noise and safety performance for operators.
Financial Summary
- 💰 Total Project Cost: £96,000 (equipment + installation)
- 💡 Annual Energy Savings: £12,500
- 🛠 Maintenance Savings: £8,800/year
- ⏱ Payback: 13 months
- 📈 ROI over 5 years: 285 %
Conclusion
This project demonstrates the measurable benefits of modernising heavy-duty motor control with ABB’s ACS880 series. The combination of reduced downtime, lower energy use, and better diagnostics delivered a full return on investment in just over a year.
If you’re running conveyors, crushers, or large pumps and still rely on DOL or star-delta starters, consider upgrading to a variable frequency drive. Use our free tools to specify the correct equipment for your site:
- ⚙️ VFD Sizing Calculator
- ⚙️ Cable Sizing Calculator
- ⚙️ Braking Resistor Calculator
- ⚙️ Motor Starter Selection Calculator
Explore our range of ABB drives and comparable options from Allen Bradley, Siemens, and Danfoss — all available for next-day UK delivery.
At Drive Outlet Megastore, we help industrial operators upgrade legacy systems to efficient, reliable automation. Contact our technical team today to discuss your next project or request a same-day quotation.
