1.Maximum Holding Torque
The holding torque is the maximum holding power (torque)the motor has when power (rated current) is being supplied but the motor is not rotating (with consideration given to the permissible strength of the gear when applicable).
2. Rotor Inertia
3.Rated Current
The rated current is determined by motor temperature rise.It is the current value that can flow to the motor coils continuously at motor standstill.
4. Basic Step Angle
The step angle is the angular distance (in degrees)that the motor moves at the input of one pulse from the driver.
5. Gear Ratio
This is the ratio in rotation speed between the input speed from the motor and the speed of the gear output shaft.
6. Permissible Torque
The permissible torque represents the torque value limited by the mechanical strength of the gear when operated at a constant speed.The total torque including acceleration/deceleration torque should not exceed this value.
7.Maximum Torque
8. Backlash
The play of gear output shaft when the motor shaft is fixed.When positioning in bi-direction, the positioning accuracy is affected.
9. Angular Transmission Error
Angular transmission error is the difference between the theoretical angle of rotation of the output shaft, as calculated from the input pulse count, and actual angle of rotation.
10. Permissible Speed Range
This is the rotation speed that the motor can be operated at with the gear output shaft.
1. Do your motors have speed-torque curves?
A: Each of our motor models measures speed-torque curves. You can submit an inquiry to tell us which product curve you need and our application engineering team will let you know if a speed/torque curve is available.
2. Why does the motor make noise
A: To meet our customers' needs for low noise motors, some of our motors are designed for quiet operation. This is achieved through our proprietary motor design methodology and material selection. If a motor becomes noisy, there are many factors to consider, such as how the motor is mounted in the application, the motor's operating load and speed, etc. Another consideration is the type of bearing selected for the motor and/or geared motor. If the application has noise requirements, the audible noise level of the proposed motor/geared motor selection should be thoroughly tested in the design before making the final selection.
3. Is the shaft on the motor customizable?
A: Yes, we have a professional and reliable development team that can customize the motor for you according to your needs. In addition to the shaft on the motor, you can also contact us for more customizable solutions
4. Are your motors/gearboxes able to withstand industrial application environments?
A: Our products are used in a variety of industrial environments such as automation, robotics, medical equipment, industrial equipment, office areas, etc. If your application requires a motor/gearbox that can be used in extreme environments, then please consult our application engineers to select the best product for your application.
5. What are the advantages of brushless DC motors (BLDC motors) against brushed DC motors?
A: Compared to brushed DC motors, brushless DC motors (BLDC motors), have no brushes and commutators and have mechanical contacts. Therefore it: 1. can be maintenance-free and has a long service life; 2. is low-noise; and 3. can operate at high speeds
6. What is the material of a brush in a DC motor?
A: A brush is usually made of metal, carbon and metal-carbon composition. Some metal brushes apply precious metals such as gold on a contact surface with a commutator. The material for a brush is carefully chosen considering electric voltage/current and from economical aspects.
7. What does the customer need to communicate before customizing the motor?
A: In order to improve the efficiency and our service quality, customers can introduce us to the following aspects before customizing the motor.
1. The main specifications of the customized motor parameters requirements, such as motor diameter, shaft diameter, voltage, speed and other basic information.
2. The specific application of the motor, that is, the motor is to be used in what products, movement, work operating environment, etc. This can help engineers in their own technical library to search for the application of the industry motor solutions to speed up the progress of technical evaluation.
3. The expected number of motor requirements, motor customization confirmation time is long (sometimes need to die sinking), so there are certain requirements for the number of custom projects, but the specific situation can be assessed by contacting our engineers.
Due to the different BLDC brushless motors in practical applications, it is often necessary to have Hall sensors. Here's a quick lookBrushless DC motor with Hall sensorAdvantages and disadvantages of the sensorless and sensorless:
Brushless motors with the advantages of Hall sensors：
1、The Hall sensor is installed inside, which can detect the position of the rotor and start smoothly;
2、The motor can start at zero speed due to the Hall sensor.
Shortcoming：
1、The price is higher than without Hall;
2、The construction is more complex than the absence of Hall.
Brushless motor without Hall advantages：
1.Longer life and reliability because no Hall can be damaged;
2.The cost is low, because there is no Hall, and there is no Hall bracket.
3.Manufacturing is simpler, and conventional motors need to adjust the Hall angle.
Shortcoming：
1.The start is not smooth, because there is no Hall to detect the rotor position, so the drive part needs to do zero point current detection, resulting in vibration when the motor starts, or even unable to start;
2.It is not suitable for applications with large loads or large load changes;
3.There are Hall drives that cannot drive such motors.
The above is a summary of the advantages and disadvantages of BLDC brushless motors with Hall sensors and brushless motors without Hall, brushless motors can be optionally equipped with Hall sensors, drives, encoders and gearboxes according to customer requirements.
What is Core-less Motor (Hollow-Shaft) Motor ?
Coreless DC motor is a special form of DC motor. These motors are used where small motors and fast acceleration are required. Compared with ordinary DC motors, this type of motor has a rotor without any iron core, so it is called coreless.
The following figure is a schematic diagram of the hollow cup DC brush motor:
Instead of the heavy iron core, in a core-less DC electric motor you’ll find:
• Housing which guides the magnetic field and acts as a magnetic return path.
• A hollow cylinder, also called a basket, with copper coils wound in a self-supporting honeycomb or skewed pattern.
• The permanent magnet fits inside the basket and therefore sits inside the rotor. An air gap separates the magnet and the housing. The magnet produces the magnetic field.
• Brushes and commutators are usually made of precious metals.
• Bearings that support the rotor so it can rotate around the magnet.
2.Advantages and Disadvantages of a Coreless Motor
Advantage：
• The high efficiency is paired with a compact design that is lighter compared to many other motors on the market. Core-less motors typically have less current loss, making them more efficient overall than the types with iron cores.
• Low draw current: It does not draw as much current as some other motors, so when powered by a battery, the battery will last longer.
• Because the Core-less motor has a lighter rotor, it does not cause as much inertia as other motors, so acceleration and deceleration can be handled quickly.
• No cogging，core-less motors do not create a misalignment of the rotor and stator magnetic circuit. This means that the motor can run very smoothly.
• Safe and durable, since there is no iron core, there is less chance of arcing and sparking between the brushes and commutator as often happens in cored motors, there will not be much electromagnetic interference (EMI), and the hollow cup motor will have a longer service life.
• Easy to control, users can easily control the motor and manage its speed.
• Low noise level and quiet operation.
Disadvantage：
In a core-less electric motor there’s no heat sink for the winding, so to cool the machine down, your DC motor’s housing must have good thermal conductivity. This is especially important if your motor will often speed up and slow down in rapid succession.
In the case of overheating, the motor will break down because the windings’ bonding adhesive will lose its efficacy. Thus, core-less DC motors won’t be able to handle an overloaded system as well as a cored motor.
3.The Many Applications of Core-less Motors
• The healthcare industry
• Robotics
• Automation & Actuators
• Laboratories
• Office equipment
86-20-28245105
wdli@rbmotor.com.cn
86-20-28245105
wdli@rbmotor.com.cn
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