Best Practices for Crusher Motor Protection in the Mining Industry

The Importance of Crusher Motor Protection in Mining Operation

In the mining industry, both crusher and compressor motor protection are essential to ensure equipment longevity and operational efficiency, especially in harsh conditions.

Crushers are the backbone of material processing, enabling the breakdown of raw ore into manageable sizes for further processing and extraction. These heavy-duty machines operate under harsh conditions, high dust levels, extreme temperatures, and variable load demands.

Crusher machines are subjected to structural overload, and this is reflected in the motor load current draw typically overfilling hopper feed chutes, resulting in overcurrent, running stall when motor is jammed at operational speed, or locked rotor preventing the motor from accelerating to operational speed on startup. These conditions are aggravated by power fluctuations, an under-voltage condition reduces motor torque by the square of the voltage reduction, or overvoltage resulting condition in the over fluxing of the motor windings.

The requirement is for a protection relay that can cater for overloading be it cyclic or continuous, undervoltage to prevent running stall conditions or a higher than rated current draw, Overvoltage to prevent the volt/hertz value being exceeded and saturating the stator core and resulting in excessive overcurrent conditions, running stall which is best described as being an electrical load shearing pin preventing the high driven and inertia load from exceeding the structural design constraints of the crusher machine as a unit.

Key reasons crusher motor protection is essential in mining include:

• Minimising Downtime: Motor failures lead to unplanned shutdowns, halting production and causing financial losses.
  

• Increasing Equipment Longevity: By protecting motors from damage, the overall lifespan of the crusher and its components is extended.
  

• Reducing Maintenance Costs: Preventive protection measures lower the frequency of repairs and replacements, saving money over the long term.

In addition to crushers, compressors are vital for powering pneumatic tools and maintaining air pressure in various mining processes, such as drilling and ventilation. These machines also operate in challenging environments, where dust, elevated temperatures, and fluctuating load demands can cause significant strain on the motors.

Effective motor protection in mining operations is not just about preventing breakdowns—it’s about optimising performance and ensuring the overall safety and reliability of the site’s electrical infrastructure.

Best Practices for Crusher Motor Protection in the Mining Industry

Protecting crusher motors in the mining industry involves implementing both proactive and reactive safety measures. Here are the best practices to follow to ensure crusher motor protection and enhance operational efficiency:

1. Use of Protective Relays

Protective relays are indispensable for monitoring motor conditions and responding to faults before they can cause irreparable damage. Relays such as the NewElec KD Relay provide advanced monitoring and fault detection, making it easier to identify issues like overload, underload, phase loss, and phase imbalance.

By integrating protective relays into crusher motor systems, mining companies can safeguard their motors from electrical issues that can cause equipment malfunctions. These devices can automatically trigger shutdowns or switch to backup systems when faults are detected, preventing further damage. Additionally, the KD Relay includes a robust data logging feature, storing 2,000 event records and 60 last fault records. This level of detailed record-keeping is critical for troubleshooting and long-term system health monitoring, allowing engineers to analyse fault patterns, prevent future issues, and maintain motor

The NewElec KD Relay offers several advanced features that make it ideal for crusher motor protection in the mining industry:

• Configurable trip settings to match the specific motor requirements, allowing precise protection customisation.
• Real-time measurement of Power Factor, Frequency, Real Power, and Apparent Power to ensure optimal power quality and motor efficiency.
• Comprehensive protection including overload, underload, and short-circuit protection to safeguard against electrical faults.
• Earth leakage and earth insulation lockout to protect both equipment and personnel by ensuring the system shuts down in unsafe conditions.
• Remote monitoring and data analysis capabilities via communication features, enabling users to oversee motor performance and preemptively address issues from a distance.

These features provide a robust, flexible solution designed to protect motors and enhance operational efficiency in harsh mining environments.

2. Overload and Short-Circuit Protection

One of the primary causes of crusher motor failure is overload, which occurs when the motor is forced to work beyond its capacity. This can happen when too much material is fed into the crusher or when the crusher encounters particularly hard material. Over time, overload conditions can cause motors to overheat, leading to insulation failure and burnout.

To prevent overloads, it’s critical to use overload relays and ensure proper coordination between the motor, crusher, and protective systems. Thermal overload protection, offered by the KD Relay, plays a vital role in preventing motors from overheating due to excessive current draw, while low voltage protection safeguards motors from damage caused by fluctuations in power supply.

The KD Relay also provides earth leakage and short-circuit protection, creating a comprehensive protection system that ensures motors are safe from a range of electrical faults. This holistic approach, combining thermal, voltage, and fault protection, ensures the motor operates within safe parameters, extending its life and minimising costly downtime.

3. Regular Maintenance and Inspection

Routine maintenance plays a vital role in protecting crusher motors. Regular inspections can help detect potential issues, such as worn-out components, damaged wiring, or compromised insulation, that may cause motor malfunctions. Proactive maintenance reduces the risk of unexpected breakdowns and extends motor life.

Here are a few key maintenance tips:

• Inspect motor bearings and lubrication regularly to prevent mechanical failure.
• Ensure that ventilation systems are clean and free from dust buildup to prevent overheating.
• Monitor motor temperature and vibration levels to identify any early signs of wear or imbalance.
• Schedule periodic testing of protective relays to ensure they are functioning correctly.

4. Proper Grounding and Surge Protection

The mining environment often exposes electrical systems to fluctuations in power supply due to lightning strikes, equipment faults, or utility failures. Surge protection devices are essential for safeguarding crusher motors from transient voltage spikes, which can cause immediate damage or degrade motor components over time. Equally important is ensuring that the motor system is properly grounded. Grounding dissipates excess electrical energy safely into the earth, reducing the likelihood of electrical faults and improving overall safety.

5. Low Voltage Protection

In the mining industry, voltage drops or fluctuations are a common problem, particularly in remote locations where the power supply may be unstable. Low voltage can severely affect crusher motor performance, causing reduced efficiency, overheating, or even complete motor failure. Implementing low voltage protection relays ensures that motors are protected from voltage drops. These relays monitor incoming voltage and disconnect the motor if the voltage falls below a safe threshold, preventing damage from under-voltage conditions.

The NewElec KD Relay is designed to offer robust low voltage protection, automatically disengaging the motor when unsafe voltage conditions are detected and restarting once conditions stabilise. This helps maintain operational continuity while protecting the motor from prolonged exposure to low voltage.

Many of these best practices for protecting crusher motors also apply to compressor motor protection, as compressors face similar risks from overloads, voltage drops, and harsh environmental conditions.

Case Study: Crusher Motor Protection in a Mining Site

To understand the real-world application of these best practices, consider a mining operation in South Africa that faced recurring motor failures in their crusher units. Despite regular maintenance, the motors were experiencing frequent overheating, leading to multiple instances of unplanned downtime and expensive repairs.

After evaluating the site’s electrical infrastructure, the company implemented a protective relay system using the NewElec KD Relay. The relay was configured to monitor motor load, power quality, and voltage levels, providing real-time data on the motor’s operating conditions.

Within months of installation, the protective relay identified a phase imbalance issue that had been previously undetected, causing the motor to draw excessive current during certain operating cycles. By addressing this issue early, the company avoided a potential motor burnout and extended the motor’s operational life.

In addition to improved motor protection, the mining site saw a reduction in downtime by 15% and maintenance costs dropped by 20%, thanks to the preventive capabilities of the protective relay system.

The Impact of Low Voltage Protection in Mining Operations

Low voltage protection is a crucial aspect of safeguarding electrical equipment in the mining industry. Mining sites are often located in remote areas, where fluctuations in the power grid or interruptions in supply can cause significant voltage drops. These drops can lead to equipment underperformance or total failure, especially for motors used in crushers and compressors.

A well-implemented low-voltage protection system ensures that motors are only allowed to operate within safe voltage parameters. By disconnecting motors during low voltage events, equipment damage is prevented, reducing the risk of downtime and extending the motor’s service life.

NewElec’s KD Relay provides enhanced low-voltage protection by continuously monitoring power quality and ensuring motors are disconnected when unsafe conditions arise. The relay can also automate motor restarts once the voltage stabilises, reducing the need for manual intervention and minimising disruption to mining operations.

How NewElec’s KD Relay Protects Crusher Motors and Enhances Efficiency

Motor relay management systems offer advanced monitoring and protection for industrial motors. These systems provide real-time data on motor performance, fault conditions, and energy usage, allowing for informed decision-making. For example, the NewElec KG/KH 3 Phase Motor Relay revolutionises motor protection with features like power quality monitoring, feeder protection, and Bluetooth LE connectivity. The ability to configure and analyse motor data remotely makes this relay an ideal solution for industries integrating into Industry 4.0 environments.

In a large industrial facility, remote monitoring with systems like the KG/KH Relay ensures that critical motor parameters are accessible to decision-makers from anywhere. This capability allows for continuous system optimisation, real-time diagnostics, and predictive maintenance, reducing the risk of failure and extending equipment lifespan. Using the KG/KH Relay, a business can analyse motor performance data, predict potential faults, and schedule maintenance well before a motor fails. This proactive approach not only prevents costly repairs but also enhances the reliability and efficiency of industrial processes.