Author: Ken Cheng

Servo Amplifiers: Diagnosing and Fixing Ground Faults

Ken Cheng Leave a comment

Ground faults in a servo amplifier system can lead to erratic behavior, unexpected shutdowns, or even permanent damage to equipment. A ground fault occurs when an unintended electrical connection exists between a live conductor and ground, causing leakage currents that disrupt normal operation. Diagnosing and fixing these faults promptly is essential for maintaining system reliability and safety.

This article provides a step-by-step guide to identifying and resolving ground faults in servo amplifier systems.

Read more: Servo Amplifiers: Diagnosing and Fixing Ground Faults

Recognizing the Symptoms of a Ground Fault

The quintessential step to repairing a ground fault is being able to recognize and identify symptoms. After all, you can’t fix a problem if you don’t know what the problem looks like. When looking for symptoms of a ground fault keep an eye out for:

Unexpected shutdowns or fault alarms (e.g., “Ground Fault” error on the drive)

Erratic motor behavior (jittering, unexpected movements, or loss of torque)

Burning smells or overheating components

Electrical noise affecting feedback devices (encoders/resolvers)

Tripped circuit breakers or ground fault protection devices

Safety Precautions

Once you’ve recognized the symptoms of a ground fault, you may have that impulse of wanting to go straight into poking around and tinkering with the drive. However, before you do that, you need to take precautionary steps to ensure your safety. Exercising the following precautions will prevent the chances of a hazard occurring, increasing your safety.

  1. Make sure the power is disconnected and verify with a multi-meter.
  2. Ensure the capacitors are discharged.
  3. Use insulated tools and wear personal protective equipment (PPE)
    – Companies like RefrigiWear offer a selection of insulated foot wear that protects against high voltage.
  4. Follow lockout/tagout procedures if working in an industrial environment.

Isolating the Fault

Once you are confident that all safety precautions have been taken and that the system is completely off and all power fully dispersed, then you can proceed forwards with isolating the fault. Here are a few ways you can isolate a fault.

Checking the Power Supply

Using a multi-meter, you can check the power supply to see if you get a low resistance rating that would indicate a short in the ground.

Checking the Motor Windings

You can test the motor windings by disconnecting the motor cables from the power supply. Next, measure the resistance between each motor phase and the ground. There should be high resistance (>1MΩ). A low resistance is an indicator of a short in the motor frame.

Check Encoders and Resolver Connections

Another way is to check encoders and resolvers for any exposed or damaged wires. You can check do this by checking for continuity between signal lines and ground. There should be no direct connection.

Inspecting the Servo Amplifier

If you need to check the servo amplifier, look for obvious visual signs like burnt components, blown fuses, or discolored PCBs. Using a multi-meter test the DC bus capacitors for leakage or short circuits. Double check proper grounding of the amplifier chassis.

Repairing the Ground Fault

While diagnosing and isolating faults are lightly challenging but doable for most people, it is advised that if you are not most versed in servo amplifiers then reach out to a professional for repairs.

Repair/Replace Damaged Wiring

If the issue is with the cables then replace any damaged or frayed cables. Also, check for strain relief on connection points to the devices. Good strain relief prevents future wear of cables. Make sure you use shielded cables for motor and feedback connections.

Address Motor Issues

Check your motor bearings as mechanical wear can cause internal shorts. If your motor windings are shorted, replace the motor.

Replacing Components

Replace blown out PCB and capacitors. Double check the amplifier is properly grounded. Be sure to check the specs before doing so.

Verify Grounding Scheme

When verifying the grounding scheme, make sure the system has a single-point ground to avoid ground loops. Also, make sure wires are properly sized and securely connected

After Repair Testing

After repairs are done, before you restore power, make sure to give another test. Use a multimeter to test resistance on motor windings and cables. After that, gradually power up the system and monitor for fault messages. Finally, run the servo motor at low speed and check for any odd sounds or for overheating.

Conclusion

Ground faults in servo amplifier systems can cause significant downtime if not addressed properly. By following a structured diagnostic approach—checking power supplies, motor windings, feedback cables, and amplifier components—you can efficiently locate and resolve the issue. Always prioritize safety, use proper testing equipment, and ensure correct grounding practices to prevent future faults.

Regular preventive maintenance, including insulation resistance checks and visual inspections, can help detect ground faults early and extend the lifespan of your servo system.

Servo Amplifier Need Replacing?

If you have a servo amplifier that needs replacing, let our team of experts help you get your system back up and running.

Contact Us

Email
Phone

The Impact of Tariffs on Industrial Automation

Ken Cheng Leave a comment

The Impact of Tariffs on Industrial Automation


Industrial automation has become a cornerstone of modern manufacturing, driving efficiency, productivity, and competitiveness. However, the increasing use of tariffs—taxes imposed on imported goods—has introduced new complexities for businesses relying on automation technologies. While tariffs aim to protect domestic industries, they can also disrupt supply chains, increase costs, and slow innovation in industrial automation. This article explores the effects they have on the automation sector.

Read more: The Impact of Tariffs on Industrial Automation

What Are Tariffs?

There exists the misconception that tariffs are a tax on exporters. However, that simply isn’t true. A tariff is an import tax that gets put upon the importing company not the exporting company. Typically the importing party pays the tariff then in turn passes the cost of the onto their customers by marking up the price of the goods imported in.




How Tariffs Affect Industrial Automation

1. Increased Costs for Automation Components

Many industrial automation systems rely on imported components, such as robotic arms, sensors, controllers, and motors. When tariffs are imposed on these goods, manufacturers face higher procurement costs. For example, U.S. tariffs on Chinese-made automation parts have forced companies to either absorb the extra expenses or pass them on to customers, leading to higher prices for automated systems.

2. Supply Chain Disruptions

Tariffs can disrupt global supply chains by making certain suppliers less competitive. Companies that depend on just-in-time manufacturing may struggle with delays and shortages if they must switch suppliers due to tariff-related cost increases. This can slow down automation adoption as businesses face uncertainty in sourcing critical components.

3. Slowdown in Automation Adoption

Small and medium-sized enterprises (SMEs) that are considering automation may delay investments due to higher costs from tariffs. This could slow overall productivity growth in manufacturing, as automation is a key driver of efficiency.

4. Encouragement of Domestic Production

On the positive side, tariffs may incentivize companies to produce automation components locally. Countries imposing tariffs often aim to boost domestic manufacturing, which could lead to increased investment in homegrown automation technologies. However, building a competitive local supply chain takes time and may not immediately offset the negative effects of tariffs.

5. Trade Wars and Long-Term Uncertainty

Ongoing trade tensions, such as those between the U.S. and China, create uncertainty for automation suppliers and manufacturers. Companies may hesitate to make long-term investments in automation if trade policies remain unpredictable.

Are There Advantages to Tariffs?

While tariffs are generally looked down upon for their disruption to the flow in the global economy. When used responsibly and with proper domestic infrastructure in place, tariffs do have certain advantages.

Reshoring of Manufacturing

Companies may bring production back to domestic markets, increasing demand for localized automation solutions.

Innovation in Alternative Technologies

Higher costs for imported components could accelerate the development of new automation technologies that rely less on tariff-affected parts.

Strategic Sourcing Diversification

Businesses may seek suppliers in countries not subject to tariffs, leading to a more resilient supply chain.

Conclusion

Tariffs can present obstacles and potential opportunities for industrial automation. While they raise costs and disrupt supply chains, they may also encourage domestic production and innovation. Companies in the automation sector must adapt by diversifying suppliers, investing in local manufacturing, and exploring new technologies to mitigate risks. Policymakers should also consider their long-term impacts on industrial competitiveness, ensuring that trade policies support—rather than hinder—technological advancement.

As automation continues to transform manufacturing, navigating trade-related challenges will be crucial for sustaining growth and maintaining a competitive edge in the global market.

Are You In Need of A Replacement Drive?

Tariffs may present themselves as an obstacle, but don’t let a broken drive or motor slow you down. Do you need to replace your drive quickly and efficiently? Let our team of experts help you get your operation back up and running.

Call
Email

Three-Phase Power

Ken Cheng Leave a comment

Three-phase power remains a widely used method for generating, transmitting, and distributing electricity. It is more efficient than single-phase and is the backbone of industrial and commercial electrical systems. This article explores the history of three-phase and its most common applications today.

Read more: Three-Phase Power

How Three-Phase Power Works

Three-phase power consists of three alternating currents (phases) spaced 120 degrees apart. This
arrangement ensures a constant energy delivery, unlike single-phase systems, which have energy
fluctuations. Key advantages include:

  • Higher Efficiency
    • Requires less conductor material compared to single-phase for the same power output.
  • Smoother Power Delivery
    • Ideal for running large motors without interruptions.
  • Flexibility
    • Can power both industrial equipment and residential areas by splitting phases.

History

Before three-phase power, electrical systems primarily used direct current (DC) or single-phase alternating current (AC). Thomas Edison promoted DC power, while Nikola Tesla and George Westinghouse advocated for AC due to its ability to transmit electricity over long distances. In 1887 Tesla developed the first AC induction motor. This motor was capable of both two and three phase. Tesla’s work demonstrated that three-phase systems were more efficient for energy transmission and motor operation.

In 1891, the first long-distance three-phase power transmission became demonstrated at the International Electrotechnical Exhibition in Frankfurt, Germany. Engineers Dolivo-Dobrovolsky, Mikhail Osipovich, and Charles Eugene Lancelot Brown successfully transmitted 175 kW of power over 175 km with minimal losses, proving the superiority of three-phase AC. The success of this demonstration paved the way for modern three-phase and by the early 20th century, three-phase power became the standard for industrial and commercial power distribution. This was primarily due to its efficiency, reliability, and ability to power large motors.

Example of first three-phase motor by Tesla.
The Tesla Polyphase was the first example of a three phase motor.

Most Common Uses for Three-Phase Power

Since its inception in the 1800’s, three-phase power has seen itself used in a wide variety of industries and applications. It sees the most use in the industrial sector. Factories use three-phase to run heavy equipment such as pumps and conveyor systems without voltage drop. You can read more information about three-phase and AC Motors in the industrial sector here.

In the commercial sector, like shopping centers, hospitals, and office, three-phase power gets used in HVAC systems to keep the buildings habitable all year long. The renewable energy sector sees three-phase being generated and fed back into the energy grid.

Three-phase power also finds a more direct to consumer use as well. It gets used to power data centers all over the world. The computational power of these server require stable high capacity voltage which three-phase excels in providing. As of late, three-phase has found their use in the electric vehicle industry being used at charging stations for people to charge their vehicles.

Conclusion

Three-phase power revolutionized electrical engineering with its efficiency and reliability. From its origins in Tesla’s innovations to its widespread use in industry and infrastructure, three-phase systems remain the standard for high-energy applications. As technology advances, three-phase will continue to play a crucial role in modern energy systems.

Average Lifespan of a PLC

Ken Cheng Leave a comment

Programmable Logic Controllers (PLCs) are integral components in industrial automation, serving as the backbone for controlling machinery and processes. Understanding their lifespan is crucial for maintenance planning and system upgrades. While exact lifespans can vary based on factors such as operating conditions and technological advancements, industry observations provide valuable insights.

Read more: Average Lifespan of a PLC

General Lifespan Estimates

Discussions among industry professionals suggest that PLCs can operate effectively for approximately 10- 20 years. For instance, some facilities have reported PLCs functioning reliably for over 30 years before replacement. However, it’s essential to recognize that these figures are anecdotal and can vary based on several factors, including the specific model, operating environment, and maintenance practices.

Schneider PLC

Factors Influencing PLC Lifespan

Several elements can impact the operational life of a PLC:

  • Operating Environment: Units in a clean, temperature-controlled settings typically outlast those in harsh environments with extreme temperatures, dust, or moisture.
  • Maintenance Practices: Regular maintenance and timely updates can extend lifespan by preventing issues that could lead to premature failure.
  • Technological Advancements: As technology evolves, newer models with enhanced features become available, which might prompt upgrades even if existing units are still functional.

Prolonging PLC Lifespan

To optimize the lifespan and performance of PLCs, consider the following strategies:

  • Standardization: Implementing standardized systems across facilities can simplify maintenance and training, leading to more efficient operations.
  • Vendor Support: Engage with manufacturers to understand their support policies, ensuring access to necessary components and technical assistance throughout the lifecycle.
  • Proactive Upgrades: Regularly assess the benefits of upgrading to newer PLC models, balancing the advantages of advanced features against the costs and potential disruptions of replacement.

Conclusion

While PLCs are designed for durability and can function effectively for decades, their actual lifespan depends on various factors. By considering operating conditions, maintenance practices, and technological developments, industries can make informed decisions to ensure the reliability and efficiency of their automation systems.

Need a PLC Replacement or Repair?

Do you have a PLC way past it’s lifespan and needs replacing? Our team of professionals can help you get your operation back and running in no time.

Contact Us

Email
Phone
Learn More About Us

Three Basic Types of Servo Motors

Ken Cheng Leave a comment

Servo motors are a crucial component in automation, robotics, and various control systems. They are designed for precision control of angular or linear position, velocity, and acceleration. There are three basic types of servo motors: positional rotation motors, continuous rotation motors, and linear motors. Each type has unique characteristics, advantages, and specific applications.

Read more: Three Basic Types of Servo Motors

Positional Rotation Servo Motors

Specifically designed for limited-angle rotation; positional rotation motors usually rotate between 0 and 180 degrees. They contain built-in feedback mechanisms, typically using a potentiometer, to control precise positioning.

Characteristics & Applications

  • Less than 180 degree rotational movement.
  • Used for precise angle adjustments
  • Compact and cost effective
  • Commonly used in camera gimbals, robotic arms, and small automated systems.
servo motors

Continuous Rotation Servo Motors

Continuous rotation motors are designed to rotate continuously in either direction, similar to a DC motor but with controllable speed and direction. These do not have position feedback but instead rely on pulse width modulation (PWM) signals to control their speed and direction.

Characteristics & Applications

  • Has full 360 degree rotational movement in either direction.
  • Speed and direction controlled via PWM signals.
  • No built-in position feedback
  • Used in processes that require continuous movement such as conveyor belts and motorized platforms.
This video explains the difference between positional and continuous servo motors.

Linear Servo Motors

Linear motors convert rotational motion into linear motion, providing precise control over movement in a straight line. These motors are commonly used in applications that require accurate positioning along a linear path.

Characteristics & Applications

  • Can convert rotational motion into linear motion
  • Very precise and accurate
  • Incorporates lead screws, belt drives, and directional actuators
  • Used in operations that require linear movement such as CNC machines and 3D printers.
servo motors

Conclusion

Each type of motor serves different applications based on its characteristics and advantages. Positional rotation motors offer precise control for limited-angle movements. Continuous rotation motors provide controllable speed and direction for continuous movement. Finally, linear motors enable precise linear motion control. Understanding these differences helps in selecting the right servo motor for any given application, ensuring efficiency and accuracy in motion control systems.

If you have found what you have read helpful then check out our article on extending your servo motor life. Feel free to also check out our article about the warning signs of a failing servo motor.

Looking for a parts?

Are you in the market for a servo motor? Let our team of experts help you get set up!

Email
Phone

Closed-Loops vs Open-Loop Control System

Ken Cheng Leave a comment

In industrial automation, servo amplifiers play a crucial role in motion control systems. They ensure precise motor operation by controlling voltage and current. One of the key distinctions in servo amplifier operation is whether they use open-loop or closed-loop control. These two control strategies significantly impact system performance, accuracy, and efficiency. Understanding their differences is essential for selecting the right control method for specific applications.

Read more: Closed-Loops vs Open-Loop Control System

Loop Control System

Before getting into the nitty gritty of knowing the differences between open and closed-loop systems, it’s probably important to establish what a loop control system is in regards to servo amplifiers. A loop control system for a servo amplifier regulates the operation of a motor by adjusting voltage and current based on a control algorithm. This system ensures the motor performs as intended by operating in either an open-loop or closed-loop configuration.

Open-Loop Control System

An open-loop control system operates without feedback, meaning the servo amplifier sends commands to the motor without verifying whether the desired motion has been achieved. This approach is simpler and cost-effective, often used in applications where high precision is not a priority. Open-loop systems are commonly found in stepper motor applications, where a predefined sequence of electrical pulses determines movement. However, these systems are susceptible to inaccuracies due to external disturbances, such as load variations or mechanical wear, since they lack a mechanism to correct errors.

Closed-Loop Control System

A closed-loop control system continuously monitors and adjusts motor performance. They perform this using real-time feedback from sensors like encoders or resolvers. Unlike open-loop systems, closed-loop control measures actual motor position, speed, or torque and compares it to the desired set-point. This allows the servo amplifier to make instant corrections if deviations occur. The results are higher accuracy, improved stability, and better responsiveness. This makes closed-loop systems ideal for precision applications such as robotics, CNC machines, and industrial automation. By compensating for disturbances, mechanical variations, and load changes, closed-loop servo amplifiers enhance reliability and efficiency, though they require more complex hardware and tuning compared to open-loop systems.

Control Loop Chart

Conclusion

The choice between open-loop and closed-loop control ultimately depends on the application’s requirements. Open-loop systems are suitable for cost-sensitive applications where precision is not critical. In contrast, closed-loop systems excel in environments demanding accuracy, adaptability, and reliability. As automation technology advances, closed-loop control is becoming increasingly prevalent, offering enhanced efficiency and performance across various industries.

Having Issues With Your Servo Amplifier?

Do you have a servo amplifier not breaking down or not working? Let our team of experts help you get back up and running as soon as possible. Call us: 800) 691-8511 or email: sales@mroelectric.com

Understanding Alarm Code 8: Fanuc Servo Motors

Ken Cheng Leave a comment

Fanuc servo amplifiers are widely used in CNC machines, offering precise control and high efficiency. However, like any complex system, they can encounter faults, with specific alarm codes indicating different issues. One such alarm is Code 8, which signals an abnormal current detection in the servo system.

Read more: Understanding Alarm Code 8: Fanuc Servo Motors

What is an Alarm Code 8?

Alarm Code 8 on a Fanuc servo amplifier typically indicates an overcurrent condition in the motor or drive system. This means that excessive current is flowing through the servo amplifier, which can lead to potential damage if not addressed promptly. The amplifier detects this anomaly and shuts down the system to prevent further harm.

Common Causes of Alarm Code 8

Several factors can contribute to an overcurrent condition in a Fanuc servo system, including:

Fanuc Alarm Code 8
  1. Motor Short Circuit – A short circuit in the motor windings can cause excessive current draw, leading to the alarm.
  2. Damaged Power Cables – If the cables between the servo amplifier and the motor are frayed, pinched, or shorted, they can create an overcurrent situation.
  3. Faulty Servo Amplifier – Internal component failure, such as a defective IGBT (Insulated Gate Bipolar Transistor) or power module, may trigger this alarm.
  4. Mechanical Overload – Excessive load on the motor, such as a jammed or misaligned mechanical system, can cause it to draw more current than normal.
  5. Incorrect Parameter Settings – Improperly set servo parameters, such as excessive gain values or current limits, can lead to overcurrent faults.
  6. Contaminants or Moisture – Dust, oil, or moisture inside the servo amplifier can cause short circuits and lead to overcurrent conditions.

Troubleshooting Steps

1. Power Cycle the System

  • Turn off the machine and disconnect power.
  • Wait a few minutes, then power it back on to see if the alarm clears.
  • If the issue persists, continue with further diagnostics.

2. Inspect Cables and Connections

  • Check the motor power cables for damage, loose connections, or wear.
  • Ensure the grounding is secure and properly connected.

3. Check for Motor Short Circuits

  • Use a multimeter to measure resistance between motor phases and between each phase and ground.
  • A very low resistance reading indicates a potential short circuit.

4. Examine the Servo Amplifier

  • Look for burnt or damaged components on the amplifier board.
  • Check for signs of contamination, such as dust, oil, or moisture.

5. Reduce Load and Verify Mechanics

  • Ensure the motor isn’t overloaded or jammed.
  • Manually move the axis to check for mechanical resistance.

6. Verify Parameter Settings

  • Check the CNC control parameters related to the servo system.
  • Restore default settings if any recent changes were made.

7. Swap Components for Testing

  • If you have a spare amplifier or motor, swap them one at a time to isolate the faulty component.

Conclusion

Fanuc servo amplifier Alarm Code 8 is a critical warning that requires immediate attention to prevent damage to the motor or drive system. By systematically troubleshooting the issue—checking cables, inspecting components, and verifying parameters—you can identify and resolve the root cause.

By understanding this alarm and taking the right corrective actions, you can minimize downtime and maintain the reliability of your CNC machine.

If your Fanuc is experiencing a different alarm code, then this previous article written covers various alarm codes that you may be able to diagnose.

Having Problems with Your Fanuc?

Do you have a Fanuc that is throwing more than just an Alarm 8? Let our team of experts help get you back up and operational quickly. Contact us via email: sales@mroelectric.com or phone: (800) 691-8511