Month: October 2018 (Page 1 of 2)

nema 17 stepper motor: can be customized

nema 17 stepper motor is applied in different projects, but gearboxes are usually required, especially in applications such as CNC machine tools and linear drives for 3D printers. A high torque, low backlash gearbox may be the most appropriate choice among these mechanical devices, and a 3D printed detachable planetary harmonic drive for the nema 17 stepper motor may be better.
This nema 17 stepper motor drives a solar gear with two planetary gears, each with a 56-tooth stationary ring and a 58-tooth output ring. Each rotation of a planet around a fixed ring causes the output ring to rotate one tooth, resulting in a reduction of nearly 100:1.
We think the “harmonic” name on this gearbox is a bit of a misnomer because the definition of the harmonic drive seems to be the periodic deformation of the curved spline, as we saw on this 3d printed strain wave gear. No matter what you call it, it’s pretty cool and can be a handy tool for all kinds of builds.
We will say that we suspect that any plastic gearbox can keep bouncing free. But we can see the benefits of design. It has some good functions. First of all, of course, it is printed entirely on 3D, except for a few screws. The perfect combination with the nema 17 stepper motor is also a very good feature, and the design on Thingivers should not be too difficult, so it can not be up and down scalable.

nema 23 stepper motor: why does it used in various types of applications

nema 23 stepper motor is often mistaken for servo motor components, but in fact, nema 23 stepper motor is as reliable as servo motors. The stepper motor achieves highly accurate positioning and speed control by precisely synchronizing the pulse signal output from the controller to the driver. nema 23 stepper motor has the characteristics of high torque and low vibration at low speed, which is suitable for short distance and fast positioning.
Suitable application
In addition to frequent start and stop point applications, nema 23 stepper motors are suitable for locating image processing processors that do not like vibration, cam drives that are difficult to adjust for servo motors, and low-rigidity mechanisms such as belt drives. In addition, by changing the ball screw drive to belt drive, the cost is greatly reduced.
High responsiveness and excellent synchronization
The notable feature of stepper motor is responsiveness. The open loop control sends one-way commands to the motor and has a high tracking mechanism for the commands. When the servo motor waits for the feedback of the encoder, the command is often “delayed”, while the stepper motor works synchronously with the pulse. Therefore, there is little “delay”, so the response is very good. Thus, nema 23 stepper motor is suitable for applications requiring synchronous operation of multiple motors.

bldc motor: how to convert it to encoder

bldc motor can be converted into a rotary encoder if you have some magnets and a bunch of coils arranged in a circle. Many people use bldc motors as rotary encoders, but they seem to use motors as generators and observe the phases and voltages. In their Hackaday Prize project, they took a different approach: they used bldc motor as coupling inductor, which seemed to be a viable way to convert motors into encoders.
At present, the project aims to send instructions to the microcontroller through serial port and rotate the bldc motor to a specific location. Future work will turn these bldc motors into tactile feedback controllers.
The experimental device of this project is a blue pill microcontroller based on STM32F103. This, combined with a set of half-bridges for driving bldc motor, is really the only thing that requires rotating motors and detecting where the motors are. The circuit uses 6 digital outputs to drive the high side and low side of the half bridge, and 3 analog inputs are used as feedback. The resulting waveforms look like three strange staircases, out of sync with each other, and the correct processing is enough to detect the position of the bldc motor.

nema 23: what is the technical explanation of it

Nema 23 is a DC motor that rotates discontinuously. Instead, a complete rotation is divided into several equal steps. Nema 23 consists of multiple stages, which are composed of multiple coils. Nema 23 rotates one step at a time by applying the energy of the input voltage to each phase in a sequence. Therefore, nema 23 converts electrical energy or input digital pulses into mechanical shaft rotation.
Nema 23 work on the principle of electromagnetism. The rotor uses permanent magnets or soft iron as the rotor, and the rotor is surrounded by an electromagnetic stator. The poles of the rotor and stator can be fixed with sharp teeth. When a voltage is applied across the terminals, the rotor is aligned or moved to the stator with minimal clearance due to magnetic effects.
The stator is energized in a certain sequence, and the rotor is also rotated to fully rotate it, and is divided into discrete steps at a specific step angle.
Nema 23 are used in equipment that requires precise positioning and speed control. Because nema 23 can accurately repeat the movement, it is used in 3D printers, camera platforms, plotters, scanners and other equipment. Due to its maximum torque at low speeds, nema 23 is also used in equipment that requires low speeds.

nema 17: what is the speed limit of it

 nema 17 has a speed limit, it is essentially the maximum speed set by the user, beyond which the nema 17 can not move forward. Why is this useful? It is mainly because the speed of nema 17 can cause vibration when it reaches the resonance frequency. This may cause the stepper motor to become unstable and overshoot. This is also the reason why it loses its torque. Sometimes it is very fast.
In order to control speed correctly, actuators should achieve maximum speed and acceleration. If you try to accelerate at a faster speed than possible, the stepper motor will stop moving. In this case, sports should start afresh. This is because the commutator loses track and should be restarted by slowly increasing the commutator frequency.
Other factors also affect stepper motor torque. The low speed torque of the stepper motor varies directly with the current. The speed at which torque drops at higher speeds depends on many factors, such as winding inductance and drive circuit, including drive voltage.
Setting speed limits will prevent nema 17 stall. This is because the torque decreases with the increase of nema 17 speed. Speed limits can be set on stepper drivers or controllers.

dc brushless motor: what’s the disadvantage of it

dc brushless motor is a typical mechatronics product which has many advantages, but it also has some disadvantages.
The disadvantages are :
The electronic speed controller (ESC) rectifier motor is needed. Additional equipment is usually required to provide throttling signals to ESC.
If ESC sensor less (favorite) rarely start torque.
ESC is designed with rotor position sensors (usually Hall effect devices) that give good starting torque, like brush motors.
Some small dc brushless motors have built-in controllers, but most large motors require separate controllers. This increases the cost and complexity of the motor solution.
You may also need a sensor to tell the dc brushless motor controller the angle of the motor shaft, although there are now sensorless motor controllers that can use motor coils as sensors to detect the angle of the motor.
The brush motor automatically completes the switch through the commutator assembly. Since the dc brushless motor does not have a commutator, it will require some electronic equipment, usually involving six MOSFETs and a microcontroller or similar arrangement to do this. Therefore, the main disadvantage of dc brushless motor is that it needs an electronic switch controller to synchronize the voltage and motor rotation to the motor coil.

nema 34 stepper motor: works well in a laser plotter

nema 34 stepper motor is applied in a laser project. Tucker Shannon invented a machine that uses lasers and some ultraviolet-sensitive paper to draw temperature and weather icons! According to Tucker Shannon’s previous work glowin-in-dark drawing, the brain inside the machine is a Raspberry Pi Zero. The laser itself is a 5MW, 405nm laser pointer with a button zipper. Two nema 34 stepper motors are used for laser orientation, one for rotation and one for height angle. Each nema 34 stepper motor is connected to a motor drive plate and connected directly to Pi.
The real beauty of Tuker’s laser plotter is that it can draw temperature and weather icons, as well as digital or analog time! The precursor to this project is his clock, which draws time using a robotic arm with a UV LED, while the other clock uses a laser-connected analogy.
The base and arm of laser were designed in SolidWorks, and then 3D printing was done. The battery has been removed from the laser and the terminal is connected directly to the raspberry pie. Pi connects to Alexa through IFTTT, so that it can control it anywhere. nema 34 stepper motor is installed vertically and the laser pointer is installed at the end.

stepper motor driver: essential for stepper motor

Stepper motor driver supports a range of industrial Ethernet and fieldbus network protocols and dedicated serial command language (SCL) for efficient network communication over Ethernet (UDP or TCP) and RS-485. This new stepper motor driver has launched by Applied Motion Products at the international packaging Expo.
Accepting advanced commands over a network connection, STF stepper motor drivers provide system designers and machine builders with the flexibility to control stepping motors using the network protocols they choose. These advanced stepper motor drivers simplify programming by incorporating motion control functions into the application software of the main logic or machine controller, rather than on a separate axis.
These DC-driven micro-step drivers also run stored programs created in the Q programming language of Applied Motion Products. Q programming provides a range of motion configuration files, multitasking, mathematical functions, conditional processing, data register operations, and more robust but simple, text-based programming languages. Operators can use STF Configurer software to configure drives and create Q programs that can be downloaded free of charge from the Applied Motion website.
STF stepper motor driver is designed for the working range of two-phase stepper motor. STF stepper motor provides advanced current control and anti-resonance algorithm, electronic suppression of motor and system resonance, to improve the smoothness of the motor and maximum torque in a wide range of speed. Torque ripple smoothing reduces motor noise and vibration. Stepper motors perform faster, quieter, smoother, and more accurately with STF stepper motor driver.

nema 17 stepper motor: the reason for using H bridge IC

nema 17 stepper motor has one winding in each stator phase. A biphasic bipolar nema 17 stepper motor will have 4 leads. In bipolar stepper motors, we do not have a common lead like a single pole stepper motor. Therefore, there is no natural reversal of the direction of the current through the winding.
The bipolar nema 17 stepper motor is convenient to operate, but the operation is complex. In order to drive the bipolar stepper motor, we need a built-in H bridge circuit driver IC. Since the current needs to be reversed to reverse the polarity of the stator pole, this can only be done through the H bridge. There are two other reasons for using H bridge IC:
1. nema 17 stepper motor has quite high traction at present. SCM pin can only provide 15mA at most. The current required by the stepper is about 10 times that of this value. The external drive IC can handle such a high current.
2. Another reason for using the H bridge is that the stator coil is only an inductor. When the coil current changes direction, a spike will be generated. An ordinary microcontroller pin can’t stand such high spikes without damaging itself. Therefore, in order to protect the microcontroller pin, the H bridge is necessary. In most nema 17 stepper motor interface projects, the most commonly used H bridge IC is L293D.

bldc motor: what is trapezoidal control of it

bldc motor is controlled by a variety of different control algorithms. Usually, the voltage of an electric motor is controlled by a power transistor as a linear voltage regulator. This is not realistic when driving high power motors. High power motors must be controlled by PWM, and the microcontroller needs to start and control functions.
Control algorithms must provide three things:
PWM voltage controlled motor speed
Mechanism of commutating motor
Methods using backward EMF or Holzer sensor to estimate rotor position.
Pulse width modulation is used to apply variable voltage to motor windings. The effective voltage is proportional to the duty cycle of PWM. When the commutation is suitable, the torque speed characteristic of bldc motor is the same as that of DC motor. Variable voltage can be used to control motor speed and available torque.
Trapezoidal commutation of bldc motor
One of the simplest control methods of DC brushless motors is the so-called trapezoidal commutation.
In this scheme, the current is controlled one-to-one at a time through the motor terminal, and the third motor terminal is always disconnected from the power supply.
The commutation of the power transistor provides energy for the appropriate windings in the stator to provide the optimal torque generation according to the rotor position. In bldc motor, the single chip microcomputer must know the rotor position and commutate at the appropriate time.

Page 1 of 2

POWERED BY automation-blog