Author: Ken Cheng

Three-Phase Power

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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.

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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

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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.

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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.

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Three Basic Types of Servo Motors

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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.

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Closed-Loops vs Open-Loop Control System

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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

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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

Optimal Operation Temperatures for Servo Amplifiers

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Servo amplifiers are critical components in motion control systems, translating low-power control signals into the high-power outputs needed to drive servo motors. To ensure long-term performance, efficiency, and reliability, maintaining the optimal operational temperature of these devices is essential. This article explores the importance of temperature management for servo amplifiers, the ideal operating range, and strategies to mitigate thermal issues.

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Why Temperature Matters

Servo amplifiers generate heat during operation due to electrical resistance and power conversion processes. Excessive heat can lead to reduced efficiency, shorter lifespan, and system failure.

Reduced Efficiency
High temperatures can increase resistance which in turn reduces the operational efficiency of your system.

Shorter Lifespan
Extreme heat accelerates wear on components like capacitors and transistors. This reduces the overall operational lifespan of equipment.

System Failure
Overheating can trigger thermal shutdowns or cause permanent damage to the amplifier.

Operational Temperature Range

Manufacturers typically specify an optimal temperature range for their servo amplifiers, often between 0°C and 50°C (32°F to 122°F). However, the exact range can vary based on the design, application, and environment. Maintaining devices within this range ensures the performance, reliability, and longevity of your equipment. Be sure to consult your owners manual regarding operational temperatures.

Factors Influencing Operational Temperatures

  1. Environmental Conditions:
    • Ambient temperature plays a significant role in how well a servo amplifier dissipates heat.
    • Humidity and dust can further impact thermal performance by reducing the effectiveness of heat dissipation mechanisms.
  2. Load and Duty Cycle:
    • Continuous or high-power operation generates more heat compared to intermittent or low-power use.
    • Applications requiring frequent acceleration and deceleration add to thermal stress.
  3. Ventilation and Cooling:
    • Insufficient airflow or obstructed ventilation can trap heat, leading to overheating.
    • Cooling mechanisms, such as heat sinks or fans, are critical in maintaining temperatures within the acceptable range.
  4. Design and Materials:
    High-quality materials and advanced designs often have better heat tolerance and dissipation capabilities.

Managing Servo Amplifier Temperatures

To ensure servo amplifiers remain within their optimal temperature range, consider the following best practices:

  1. Monitor Temperatures:
    • Use built-in thermal sensors or external monitoring systems to track operating temperatures in real-time.
  2. Ensure Adequate Ventilation:
    • Install servo amplifiers in locations with sufficient airflow.
    • Keep ventilation ports clear of dust and debris.
  3. Implement Active Cooling:
    • Use fans or air conditioning systems for environments with high ambient temperatures.
    • In some cases, liquid cooling may be required for high-power applications.
  4. Optimize Load Profiles:
    • Avoid overloading the servo amplifier by ensuring the motor and amplifier are properly matched.
    • Design the motion profile to minimize unnecessary stress.
  5. Regular Maintenance:
    • Clean and inspect the servo amplifier regularly to remove dust and ensure all cooling mechanisms function properly.
    • Replace aging components that may impact thermal performance.

Conclusion

Maintaining servo amplifiers within their optimal operational temperatures is crucial for performance, reliability, and longevity. By understanding the factors that influence temperature and implementing effective thermal management strategies, operators can maximize the value and efficiency of their motion control systems. Proper installation, monitoring, and maintenance are key to keeping these vital components running smoothly in any application.

You read more about the basics of servo amplifiers here.

Overheated Amplifier Needs Replacing?

Do you have a servo amplifier that’s overheated and in need of replacement? Reach out to our team and let’s get your operations back up and running! Email us: sales@mroelectric.com or call: (800) 691-8511.

Finding the Right Fanuc Servo Amplifier

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Like many things in life, Fanuc servo amplifiers are not a one size fits all situation. Different servo amplifier models appropriately fill the roles of different scales of operation. You have to consider not only the cost of the amplifier, but also how well does it fit the needs of your operation.

Read more: Finding the Right Fanuc Servo Amplifier


Fanuc, a leading manufacturer of CNC systems and automation technologies, offers a wide range of amplifiers designed to control servo and spindle motors in industrial machinery. These amplifiers play integral roles to the precise operation of CNC machines. They fall into categories based on their capabilities, applications, and technological advancements. Below is an overview of the different series of Fanuc amplifiers:

Alpha i-D Series

FANUC’s new generation amplifiers have a smaller footprint, needing up to 30% less space than previous models. With an expanded multi-axis amplifier lineup, this series of drives saves energy use through its new low-consumption design as well as reduced fan operation. A brake control circuit is integrated into the servo amplifiers and a Leakage Detection Function is available in all Alpha i-Ds. Plus, an easy fan replacement feature makes these drives a breeze to maintain. The Alpha i-D Series Amplifiers can be connected to current FANUC CNC Plus Series models.

  • Features:
    • Integrated power supply and servo modules.
    • Compact design for space-saving installation.
    • High-speed communication with CNC systems.
    • Compatible with a wide range of Fanuc motors.
  • Applications:
    • General-purpose CNC machines, such as lathes and milling machines.
    • Suitable for both small and large-scale industrial operations.

Alpha i Series

The Alpha i series is an upgraded version of the Alpha series, offering enhanced efficiency and more advanced features.

  • Features:
    • High-efficiency power modules reduce energy consumption.
    • Advanced diagnostics and monitoring capabilities.
    • Support for multiple axis control in a single unit.
    • Improved thermal management for longer service life.
  • Applications:
    • High-precision CNC machinery.
    • Industries requiring energy-efficient operations.


Beta i Series

The Beta series amplifiers are designed for cost-effective operations without compromising on performance.

  • Features:
    • Simple design for easy installation and maintenance.
    • Economical choice for smaller machines.
    • Integrated power supply and servo amplifier units.
    • User-friendly setup and configuration.
  • Applications:
    • Entry-level CNC machines.
    • Compact machinery with moderate performance needs.

Spindle Amplifier Series

Fanuc’s spindle amplifiers are dedicated to driving spindle motors, which require high power and speed control.

  • Features:
    • High torque and speed control capabilities.
    • Advanced thermal and power management.
    • Integrated monitoring and diagnostics.
    • Support for heavy-duty applications.
  • Applications:
    • High-speed milling and grinding machines.
    • Heavy-duty lathes and turning centers.

What to Consider

Now that we’ve listed a selection of servo amplifiers that Fanuc has to offer, the question of “Well how do I know which to get?” arises. Before making that decision here are some things to consider that may be helpful.

  • Machine Requirements
    • What is the power, torque, and precision needs of your operation?
  • Compatibility
    • Make sure that the servo amplifier matches the CNC and motor in use.
  • Scalability
    • Is your system modular? Can it be scaled for future upgrades?
  • Cost-Efficiency
    • Does the long term gain and efficiency justify the initial cost?

Conclusion

Choosing there right servo amplifier can be a challenging task, but going through and observing the cost and benefit analysis of each series as well as the technical compatibility can make the process of getting a new servo amplifier a less frustrating experience.

Need a Fanuc Servo Amplifier?

To make your acquisition of a Fanuc servo amplifier an even easier experience, our team of experts can help you get connected with the right machine that suits your needs perfectly. Call: +18006918511 or email: sales@mroelectric.com