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The Role Of Motors In Industrial Automation

POSTED 03/04/2024  | By: Roy Sarkar, A3 Contributing Editor

Motors are the heartbeat of industrial automation, pivotal in powering the machinery that drives manufacturing processes. Their ability to convert electrical energy into mechanical motion meets the need for precise and controlled movements in many robotic systems.

While manufacturing trends focus on the IoT, artificial intelligence (AI), and digital twins, the humble motor gets the job done on the front line. On automotive assembly lines, motor-equipped robots weld and paint. Food services use specialized washdown motors in damp environments such as beverage processing and bottling.

Let’s dive into the mechanics and business value of industrial motors.

Types of Industrial Motors

The use cases for motors are aligned to business value, says Warren Osak, founder and CEO at Electromate Inc. “Motors are crucial for tasks where consistency and efficiency are key, like assembly, packaging, and material handling. We also see them used for scaling production and maintaining quality, which are essential to competitive industrial environments.”

Motors are classified into different types:

  • DC motors, powered by direct current, are most suitable for applications demanding continuous and controlled motion. Their simple design and ease of speed control make them ideal for a wide range of industrial automation tasks.
  • AC motors, powered by alternating current, are known for their efficiency and reliability. They are often preferred for high-power and constant-speed applications, such as pumps, compressors, and conveyors.
  • Servo motors are closed-loop systems that use positional feedback to maintain a desired position or speed in real time. They are best suited for high-precision tasks, like CNC machining, robotics, and automated inspection systems.
  • Stepper motors move in discrete steps without the need for positional feedback, allowing for precise control over position and speed. They are ideal for applications requiring accurate positioning and designs that are simpler than servo motors, such as 3D printing and medical devices.

The Growth of Brushless Motors in Industrial Applications

The increased use of brushless motors is driven by technological advancements and growing demand for efficient and reliable systems. As the name implies, brushless motors replace the mechanically driven functions of brushed motors with an electronic drive. The electronic controller creates a variable current that powers a magnetic field to create the motor’s spinning motion.

Brushless DC (BLDC) motors are typically used in drone and conveyor applications, where control and efficiency are paramount. Brushless AC (BLAC) motors are commonly used in HVAC systems and electric vehicles, where reduced complexity and longevity are most important.

Comparing the Different Types of Motors

Each motor type offers unique advantages, Osak explains. “DC motors are known for their simple speed control and high torque at low speeds, suitable for applications like electric vehicles. AC motors are widely used for their durability and efficiency, ideal for continuous-duty applications like conveyor systems.”

Mike Allen, director of Sales-Material Handling Products at Automation Controls Group, says the unique requirements of a given application will drive the choice of motor. “Servos, for example, are generally compact and lightweight and consume power based strictly on the demand, making them especially suitable for energy-efficient applications. They’re also well-suited for multi-axis control systems with complex movements and coordination, as in robotic arms.

“By contrast, stepper motors can be more cost-effective than other motor types. The tradeoff is that they need careful programming to avoid missed steps and counter the absence of built-in feedback for position verification. They continue to be widely used in industrial robotics as their precise control and ease of integration make them well-suited for applications where multiple axes of movement are required.”

Allen expects manufacturers to make tradeoffs when choosing between the different types of brushless motors. “BLDC motors offer high efficiency and reliability with low maintenance needs due to the absence of brushes. BLAC motors have these same advantages on top of the robustness and reliability of AC components. The right choice depends on budget, business goals, application requirements, and maintenance considerations.”

Considerations for Choosing the Right Motor

Businesses rely on motors to run their operations reliably and effectively regardless of the application. Consider these four factors when selecting your next industrial motor:

1. Performance Requirements

Understanding the specific performance requirements of a given application determines which features will take priority when you are selecting a motor.

“High-speed operations require motors with fast response times, precision tasks need high accuracy, and heavy-duty applications demand high torque,” Osak points out. “Successfully addressing such requirements plays a major role in meeting business objectives around productivity, energy efficiency, scalability, and maintenance costs. High-efficiency motors, for example, can reduce energy consumption, while reliable and precise motors can enhance product quality and reduce downtime.”

2. Environmental Conditions

Factors such as temperature, humidity, and exposure to dust or chemicals will also determine your motor selection. For applications in harsh environments, like foundries or chemical plants, motors with robust enclosures and resistance to environmental stressors are essential.

Allen lists the reasons why aligning a given motor’s specifications and design with environmental conditions is essential for optimal operation:

  • Motors have temperature ratings, and exceeding them can result in overheating and premature failure. High temperatures diminish efficiency and may require extra cooling measures. In cold settings, motors may encounter challenges related to lubrication and stiffness.
  • Motors in humid environments may require specialized coatings or enclosures to prevent water ingress and corrosion. Electrical connections also can be affected, contributing to electrical failures.
  • Motors operating in dusty or contaminated surroundings may require sealed enclosures and proper ventilation to prevent particles from causing wear or damage.
  • Some environments expose motors to excessive vibration or shock. Motors selected for these conditions should be designed to endure such mechanical stresses.
  • At higher elevation, decreased air density can impact cooling efficiency. Motors in elevated locations may require adjustments for proper cooling and sustained performance.

3. Power Supply and Voltage

Matching the motor’s power supply requirements with the available voltage is critical. An inadequate power supply can lead to underperformance or damage, while an oversized supply can reduce the motor’s life expectancy.

The key power supply considerations are:

  • Voltage and current compatibility: Motors operate within specific voltage and current ranges. A mismatched voltage can lead to inefficiency, overheating, or failure.
  • Power rating and capacity: Motor power ratings indicate their ability to convert electrical power. Compatibility with the power supply prevents overload or underutilization.
  • Frequency (AC motors): AC motors operate at specific frequencies. Matching the power supply frequency is crucial for efficient synchronous operation.
  • Start-up and operating conditions: Motor start-up conditions are influenced by the power supply and selecting units with the right characteristics prevents issues during initial demands.
  • Control system compatibility: To work optimally in applications that require high precision, such as motion control and 3D printing, motors must be compatible with the requirements of their power supply control systems.
  • Efficiency and energy consumption: Matching the motor to the power supply is essential for promoting energy efficiency, which is central to minimizing operational costs and ensuring sustainability.
  • Safety: Understanding power supply requirements is vital for implementing adequate safety measures. Higher DC voltage motors may require additional precautions compared to those running on lower voltages.

4. Cost

“Budget constraints influence the type and quality of motors that a manufacturer can use,” Osak says. “While higher-quality motors may have a higher upfront cost, they can offer long-term savings through better efficiency and lower maintenance costs. Balancing the initial investment with long-term benefits is crucial.”

Understanding Total Cost of Ownership (TCO) aids in making informed decisions within budget limitations, Allen says. “TCO analysis considers the overall costs throughout a motor’s lifecycle. Maintenance costs are one factor, as motors with lower maintenance requirements, like brushless DC motors, may offer long-term cost savings resulting in a lower TCO. Evaluating long-term energy savings is also essential when aligning motor choices with budget constraints. Additionally, motors with specialized features or customization options often come at a higher price.

“Assessing the necessity of all features within the budget is crucial for informed decision-making. Organizations with larger budgets may benefit from bulk purchases, leading to potential discounts. Finding this flexibility allows for the consideration of higher-end motor options.”

Integration with Control Systems

Compatibility with existing control systems helps to ensure smooth integration and operation of the motor. In industries adopting Industry 4.0 practices, for example, integrating motors with smart control systems is essential for effective data-driven decision-making and predictive maintenance.

Allen identifies key strategies to facilitate the integration of motors into control systems:

  1. Gain a thorough understanding of the specifications and needs of the current control system, including communication protocols and feedback mechanisms.
  2. Seek guidance from motor and control system manufacturers to address compatibility issues and obtain recommendations.
  3. Look for motors featuring standardized communication interfaces, such as Profinet, Modbus, Ethernet IP, or EtherCAT, to ensure compatibility.
  4. Confirm that the motor’s communication protocols align with those supported by the control system, including any Industry 4.0 or IIoT requirements.
  5. Ensure that the feedback mechanisms employed by the motor, such as encoders, align with the control system’s ability to interpret and use the feedback data.
  6. Prior to full-scale implementation, perform compatibility tests to identify and address potential issues in the interaction between motors and the control system.
  7. If a separate controller is necessary, confirm its compatibility with the existing control system, considering communication protocols and command signals.
  8. Implementing motors controlled by PLCs enhances adaptability to diverse control systems, allowing for seamless integration.
  9. If necessary, consider updating or retrofitting control systems to support modern motor technologies, promoting overall system efficiency and longevity.

The best motor is the one that meets the application’s requirements. From the simplicity of DC motors to the precision of servo motors, each type has its strengths. Careful consideration of factors specific to your business is essential for success.

By staying informed about the latest motor technologies and best practices, industrial manufacturers can optimize their operations, enhance efficiency, and stay competitive.