Category: General Topics

1.Brief of variable reluctance stepper motor
A Variable Reluctance stepper motor is a type of motor that rotates in precise angular steps by aligning a soft iron rotor with a rotating magnetic field generated by the stator. Unlike other stepper motors, VR motors have a soft iron rotor without permanent magnets and operate by seeking the path of least magnetic resistance (reluctance). Sequential energization of the stator phases creates a rotating magnetic field that the rotor follows, moving in distinct, repeatable steps with each pulse of current.

2.Working principle of variable reluctance stepper motor
1.Soft Iron Rotor: The rotor is made of a ferromagnetic material (soft iron) with salient teeth but contains no permanent magnets.
2.Stator Windings: The stator has wound coils that are energized in a specific sequence.
3.Magnetic Field: When a stator phase is energized, it creates a magnetic pole.
4.Minimizing Reluctance: The rotor’s teeth are attracted to the energized stator poles because this alignment provides the path of least magnetic reluctance (resistance) through the magnetic circuit.
5.Step-by-Step Movement: By sequentially switching the current to different stator phases, a rotating magnetic field is produced, causing the rotor to follow and align itself in small, precise angular increments.

3.Selection tips of variable reluctance stepper motor
1.Torque selection: Choose the right motor model according to the required torque size (i.e. the torque size of the object to be driven). ‌ Generally speaking, if the torque is below 0.8N.m, you can choose 20, 28, 35, 39, 42 (the diameter or squareness of the motor body, unit: mm); if the torque is around 1N.m, it is more appropriate to choose a 57 motor; if the torque is several N.m or more, you should choose a stepper motor with specifications such as 86, 110, 130, etc. ‌
2.Speed ​​selection: The output torque of the motor is inversely proportional to the speed. At low speed, the output torque of the motor is large; while at high speed, the torque will decrease. ‌ Choose the right motor according to the needs of the working environment. If a high-speed motor is required, a motor with a slightly smaller inductance should be selected to obtain a larger output torque.
3.No-load starting frequency selection: The no-load starting frequency of the stepper motor is an important indicator, especially in applications that require instantaneous frequent starting and stopping. If you need to start directly to achieve high-speed operation, you should choose a motor with a higher no-load starting frequency, such as a reactive or permanent magnet motor.
4.Phase number selection: Motors with different phase numbers have different working effects. The more phases, the smaller the step angle can be made, and the vibration during operation is relatively smaller. In most occasions, two-phase motors are used more. However, in high-speed and high-torque working environments, three-phase stepper motors are more practical.
5.Use environment: Select according to the use environment of the motor. For example, special stepper motors that are waterproof and oil-proof are suitable for some special occasions, such as underwater robots, etc.

4.Maintenance tips of variable reluctance stepper motor
1.Environmental Maintenance:Dust, moisture, and debris can cause bearing wear and electrical faults. Regularly clean the motor casing and its surroundings, especially in industrial environments.For harsh environments, use protective covers or consider IP-rated stepper motors designed for rugged use.
2.Electrical Maintenance:Correctly configure the stepper driver’s current, voltage, and step frequency to the specific motor model. Regularly check the operating temperature and ensure it remains below the motor’s rated thermal limit to protect internal components. Utilize the stepper drive’s feature to reduce current when the motor is not moving, which can help decrease heat.
3.Mechanical Maintenance (If Applicable):While many VR motors are maintenance-free, check the manufacturer’s recommendations. Some may require occasional lubrication of bearings or external linear components. Look for signs of wear on bearings, which can cause increased resistance and stalling. Also, check for other internal issues like winding short circuits or rotor eccentricity.
4.Wiring Best Practices:Ensure all wiring adheres to the motor and driver’s specific wiring diagrams.Keep high-voltage power cables separate from low-voltage and control wiring to prevent electrical interference.Employ shielded cables for power wiring and ground them properly to the enclosure to reduce noise.

1.Basic introduction of hollow rotary actuator
A hollow rotary actuator is a type of rotary actuator that features a central hollow bore through its output shaft. This design allows for the passage of cables, wiring, or piping through the center of the actuator, simplifying equipment design and potentially reducing size and weight. These actuators are often used in factory automation, robotics, and other applications where space is limited and the routing of utilities is critical.

2.Key features of hollow rotary actuator
1.Hollow Bore:The defining characteristic is the central opening in the output shaft, which can accommodate various cables, wires, or tubing.
2.Integration:Hollow rotary actuators often integrate the motor, encoder, and driver into a single, compact unit, simplifying wiring and control.
3.High Rigidity:Many models incorporate cross-roller bearings to handle significant thrust, radial, and moment loads, ensuring high accuracy and durability.
4.Flexibility:They are available in various sizes and with different mounting options to suit diverse applications.
5.Control:Some models offer advanced control features, including stand-alone control via a programming language, USB/RS-485/Ethernet communication, and compatibility with different amplifier types and communication networks.

3.Maintenance tips of hollow rotary actuator
1.Lubrication:Hollow rotary actuators often require specific types of grease or oil. Refer to the manufacturer’s specifications for the correct type and quantity. Regularly check for grease leaks, especially if the actuator is installed in a position where leakage could cause contamination.
2.Oil Level Check:If your actuator uses oil, check the oil level regularly. Locate the oil level screw plug and remove it to check the oil level. If the oil level is low, add the correct amount of the specified oil. Ensure the actuator is cool before checking the oil level, especially after operation.
3.Visual Inspection:Regularly inspect the actuator for any signs of wear, damage, or loose components. Check the mounting screws and ensure they are tightened to the correct torque. Look for any unusual noises or vibrations during operation, which could indicate a problem.
4.Correct Installation:Ensure the actuator is mounted correctly using the specified mounting holes and screws. Avoid using the positioning pins to remove or loosen the actuator, as this can affect positioning accuracy.
5.Environmental Considerations:Keep the area around the actuator clean and free of debris. Avoid operating the actuator in extreme temperatures or environments that could damage it. If the actuator is used in an environment with potential hazards (e.g., flammable materials), take appropriate safety precautions.
6.Safety Precautions:Always disconnect the power supply before performing any maintenance or inspection. Do not touch the actuator or its moving parts during operation. Use the correct actuator and driver combination as specified by the manufacturer.

4.Main application scenarios of hollow rotary actuators
1.Industrial automation‌: In the field of industrial automation, the hollow rotary actuator is one of the key components for realizing automated production lines. It can accurately transmit rotational motion to various mechanical equipment to ensure the accuracy and efficiency of the production process‌.
‌2.Robotics: In the field of robotics, hollow rotary actuators help robots achieve more flexible and precise motion control, thereby improving the robot’s work efficiency and precision. For example, using hollow rotary actuators at the robot joints can facilitate pipeline layout, make the manipulator move more smoothly, and perform complex tasks.
‌3.Medical equipment: In the field of medical equipment, hollow rotary actuators are used in surgical robots to ensure the precise movement and positioning of surgical instruments and improve the accuracy and safety of surgery. In addition, it can also be used in medical imaging diagnostic equipment to improve the accuracy of diagnosis.
‌4.Aerospace: In the field of aerospace, hollow rotary actuators ensure the accurate movement and positioning of various precision components, providing strong guarantees for the smooth progress of aerospace missions.
‌5.CNC equipment: In CNC machine tool equipment, hollow rotary actuators, as the fourth machining axis of the machine tool, can achieve more dimensional machining operations, expand machine tool functions, and improve machining accuracy.
‌6.Intelligent logistics system‌: In the intelligent logistics system, hollow rotary actuators are used in automated inspection equipment and industrial machinery equipment to improve inspection accuracy and production efficiency‌.

1.Brief of harmonic reducer gearbox
A harmonic reducer gearbox, also known as a harmonic drive, uses the elastic deformation of a flexible gear (flexspline) to achieve high reduction ratios and precise motion control. It typically consists of three main components: a wave generator, a flexspline, and a circular spline. The wave generator, an elliptical component, deforms the flexspline, causing it to engage with the circular spline at two points. This engagement, combined with the difference in tooth count between the flexspline and circular spline, results in a significant reduction ratio.

2.Working principle of harmonic reducer gearbox.
1.The wave generator rotates, causing the flexspline to deform and engage with the circular spline at two diametrically opposed points.
2.As the wave generator continues to rotate, the points of engagement move around the circumference of the circular spline.
3.Because the flexspline has fewer teeth than the circular spline, each rotation of the wave generator results in a small relative rotation of the flexspline in the opposite direction.
4.This difference in tooth count and the controlled deformation of the flexspline create the high reduction ratio.

3.Importance of harmonic reducer gearbox
1.High Reduction Ratios: Harmonic drives can achieve significantly higher speed reduction ratios compared to traditional gear systems in the same space. This allows for smaller, lighter, and more efficient overall designs.
2.High Torque Capacity: Due to the large number of teeth in simultaneous contact and surface contact, harmonic drives can handle high torque loads effectively. This makes them suitable for demanding applications where high force or power transmission is needed.
3.High Precision and Accuracy: Harmonic drives are known for their low backlash and high repeatability, making them ideal for applications requiring precise positioning and motion control. This is critical in robotics, where accurate movements are essential.
4.Compact Size and Light Weight: The design of harmonic drives allows for a compact and lightweight construction, which is advantageous in space-constrained environments or when weight is a critical factor.
5.Smooth and Quiet Operation: The continuous engagement of teeth in harmonic drives results in smooth and quiet operation, minimizing vibrations and noise.
6.Versatility: Harmonic drives can be used for both speed reduction and speed increase, making them adaptable to various mechanical system requirements. They can also change the direction of torque transmission.
7.Applications: Harmonic drive gearboxes are widely used in a variety of industries, including:robotics,aerospace,medical devices,semiconductor manufacturing,and other applications(industrial automation, CNC machines, telescopes, and more).

4.Maintenance methods of harmonic reducer gearbox
‌1.Cleaning and inspection‌: Clean the harmonic reducer gearbox regularly. It is recommended to perform external cleaning at least once a month, use a soft cloth or compressed air to remove dust and debris, and avoid using corrosive chemicals. Regularly check the wear of gears, bearings and other moving parts.
‌2.Lubrication‌: Choosing the right lubricant is crucial to the performance of the harmonic reducer gearbox. The right lubricating oil or grease should be selected according to the manufacturer’s recommendations and the working environment. The lubricating oil should be checked and replaced every 1000 to 2000 hours of operation, and the grease should be replenished or replaced every 6 to 12 months.
‌3.Temperature control‌: Monitor the temperature of the harmonic reducer gearbox during operation. Excessive temperature will affect its performance and life. It is recommended to install a temperature sensor to monitor the temperature of the equipment in real time and ensure that there is enough space around it for heat dissipation. If the ambient temperature is high, you can consider adding a cooling fan or using a cooling system‌.
‌4.Load management‌: Avoid long-term overload and the load should be reasonably distributed according to the manufacturer’s specifications. Avoid sudden excessive torque during startup to reduce the impact on gears and bearings‌.
‌5.Electrical maintenance‌: Check the electrical connections regularly to ensure that there is no looseness or corrosion. For harmonic reducer gearboxes used outdoors, appropriate protective measures such as waterproof and dustproof covers should be taken to prevent damage to electrical components‌.
‌6.Fault diagnosis‌: If the harmonic reducer gearbox makes abnormal sounds or vibrations during operation, it should be stopped and checked immediately. Use vibration analysis tools to regularly detect the vibration of the equipment. Abnormal vibration may be a sign of damage to internal components‌.
‌7.Regular inspection and maintenance‌: Develop a detailed maintenance plan based on the equipment’s usage and the manufacturer’s recommendations, including a schedule for cleaning, lubrication, inspection, and replacement of parts.

1.Basic introduction of linear guide rail.
A linear guide rail, also known as a linear motion guide or slide rail, is a mechanical component used to enable precise and smooth linear motion in various machines and equipment. It consists of a rail and a carriage (or slider) that moves along the rail, often incorporating rolling elements like ball bearings to reduce friction and ensure accurate movement.

2.Components of linear guide rail
1.Rail:The rail is the stationary component, often a flat surface, that guides the carriage. It’s typically made of hardened steel for strength and durability, with a surface finish that minimizes friction.
2.Carriage (Slider):The carriage is the moving component that attaches to the load or mechanism requiring linear motion. It houses the rolling elements and moves along the rail.
3.Rolling Elements:These are either balls or rollers that recirculate between the rail and the carriage, reducing friction and enabling smooth linear movement.

3.Performance advantages of linear guide rail
1.High Load Capacity and Rigidity:Linear guide rails, with their larger contact surface and rolling elements, can handle significantly heavier loads compared to other linear motion systems like linear bearings. Their robust design minimizes deflection and ensures stable movement even under stress.
2.Precision and Accuracy:Linear guide rails are designed for high-precision applications, offering exceptional positional accuracy and repeatability. This is crucial in industries where precise linear motion is paramount.
3.Smooth and Low-Friction Motion:The rolling elements (balls or rollers) within the guide rail system minimize friction, resulting in smooth and efficient linear movement.
4.Long-Term Reliability and Durability:Linear guide rails are built to withstand continuous operation and demanding conditions. Their robust construction and resistance to wear and deformation ensure long-term reliability and reduced maintenance requirements.
5.Versatility and Configurability:Linear guide rails are available in various sizes, accuracy classes, and preload options, allowing for customization to meet specific application needs.
6.Ease of Installation and Maintenance:Linear guide rails often feature straightforward installation processes, and their modular design simplifies maintenance and replacement.
7.Cost-Effectiveness for Extended Lengths:In applications requiring long travel distances, linear guide rails can be a more cost-effective solution compared to some alternatives.

4.Common faults of linear guide rail.
1.Excessive wear and tear is one of the most common issues encountered with linear guide rail systems. Over time, the constant motion and friction can lead to wear on the guide rails, resulting in decreased accuracy and performance. One of the main causes of excessive wear and tear is improper lubrication. Insufficient or improper lubrication can increase friction and accelerate the wear on the guide rails. Additionally, contamination from dust, debris, and other particles can exacerbate the issue.
2.Another common issue with linear guide rail systems is misalignment. Misalignment can occur due to various factors, such as improper installation, accidental damage, or thermal expansion. Misaligned guide rails can result in uneven wear, decreased accuracy, and increased friction, leading to poor performance of the system.
3.Sticky or binding motion is another issue that can arise with linear guide rail systems. This problem is often caused by the accumulation of dirt, debris, or insufficient lubrication. When foreign particles get trapped between the guide rails and the carriage, they can hinder the smooth movement, leading to sticking or binding motion. Inadequate lubrication or the use of the wrong type of lubricant can also contribute to this issue.
4.Excessive noise from the linear guide rail system can indicate underlying issues that need to be addressed. Noisy operation can be caused by various factors, including wear and tear, misalignment, or lack of proper lubrication. Additionally, damaged or worn components within the system can contribute to increased noise during operation.
5.Poor performance and accuracy are overarching issues that can stem from various factors affecting linear guide rail systems. These issues can impact the overall efficiency and precision of the system, leading to potential setbacks in production and operations. Poor performance and accuracy can result from wear and tear, misalignment, improper installation, or inadequate maintenance practices.

Brushless DC motors offer several advantages over traditional brushed DC motors, including higher efficiency, longer lifespan, and greater reliability. However, to operate a BLDC motor, you need a specialized motor controller that provides the necessary electrical signals to control the motor’s speed, direction, and torque. Let’s explore how to select a brushless DC motor controller that will meet the needs of your application.

When it comes to choosing a brushless motor, there are a few key considerations that you should keep in mind, such as:
Speed and Torque: One of important considerations when choosing a brushless motor is its speed and torque capabilities. It is important to select a motor with enough power to complete the desired task while not overloading it.
Size: Another key factor to consider is the size of the motor, which will determine the space requirements of your application. Smaller, lighter motors are typically more efficient but may have a different torque or power output than larger motors.
Cost: As with any purchase, cost is an important factor in selecting a brushless motor. When comparing prices, consider factors such as efficiency and durability to determine which motor is suitable for your application.
Control System: Depending on the application, you may need a specific control system to operate the motor. Either analog or digital systems can control brushless motors, so make sure to select one that is compatible with your specific needs.
Environment: Consider the environment in which your motor will be operating. Different motors are designed to work in different environmental conditions, so select one that suits your application’s environment. This includes factors such as temperature, humidity, and dust levels.

Buying a BLDC motor requires a careful attention to several details. These include the parameters that describe the motor’s working characteristics, or the brushless DC motor specifications. Matching these with your project needs, you can be sure to buy a BLDC motor that suits the intended purpose or use. That’s because BLDC motors come in many different types and making the wrong choice can mean a failed project. If you have any question in choose BLDC motor, please feel free to contact us.

Following chapter is a very high overview. Please read further down about more practical info about the drive and motor types. But basics presented here is pretty universal and widely used in DIY community.

So- what we need to get these motors going? Let’s break it down to components and explain each part briefly. Commonly you need following parts to drive a stepper motor.

1. Driver
2. Microcontroller
3. Power supply

I didn’t include a power supply for (micro)controller here since it’s self-explanatory. A microcontroller like in this case Arduino- gets its power from the USB cable or battery.

Stepper Motor Driver
As we know- stepping motor can be moved one step at a time by applying electricity to coils in the correct order (and polarities). You could do this manually with some switches– step by step, but it has no practical use other than learning. This is where the driver comes into play.

The driver is doing the heavy lifting and it hides all the complexity behind a simple interface. It makes correct windings to be excited in the correct way based on the input signals. They usually have only 2 input pins which take commands in form of digital high and low. One sets the direction of rotation and other is for step commands.

Steps are given as digital pulses. After each step (HIGH) there must be (LOW) input for a moment. So drive can detect when new step command is given. If there is are no pulses given- there will be no steps done by the drive and motor.

Direction input pin can be LOW or HIGH all the time, while steps are made, depending on the direction needed. Direction does not need impulses.

Note: Some small unipolar stepper motors are driven via transistor arrays or chips like uln2003 and ln2004. There can be 4 control wires instead of 2 from the microcontroller. In that configuration, the microcontroller is directly telling which wires (coils) to energize by turning correct ones on each step “manually”. Look at example schema on the Arduino page.

Microcontroller
It’s possible to make motors move by touching the step pin on driver manually with HIGH wire. But that would not be very practical other than testing. This is why microcontroller comes into play. Microcontrollers can give many hundreds or even thousands of impulses per second so the motor can be rotated very fast and accurate.

Which has higher torque? nema 17 or nema 23？

How to choose the NEMA 23 or the NEMA 34 stepper motors?