Saturday, September 29, 2018

The difference of analog and digital drives

Faster and cheaper processors currently being turned out by the silicon foundries are making it easier to justify digital stepper motor driver instead of traditional analog drives. But do digital drives offer a clear advantage for more applications?

The difference of analog and digital drives

Compare the two approaches by first analyzing the classic analog drive shown in the diagram. In this case, the drive is configured as a torque amplifier. An external controller generates a ±10-Vdc command signal. The drive monitors the motor winding current and estimates the mechanical torque. A compensator takes the difference and generates a voltage command signal. Next, a pulse-width-modulated signal is applied to an inverter, which switches the correct voltages to the motor.

One of the main advantages of a digital drive system is the ease with which new features can be added. If it has sufficient processing power, additional functions can be added for only the cost of development. For example, consider the active damping feature first introduced on steppers. The analog drive circuitry required more than 100 components. Obviously, this had to be accounted for early in the design. When the active damping feature was implemented in the digital drive, it merely consisted of several lines of code. With sufficient processing power, features such as encoderless stall detection, which would be nearly impossible to do in analog, can be economically added to the drive.

The difference of analog and digital drives


Another advantage of a digital drive is the ease with which it is field upgradable. Using flash memory, new software can be posted on a Web site or e-mailed to customers. This lets new features and bug fixes be easily delivered to the field without sending the drive back to the factory. Custom software specifically tailored to a single customer's application is also possible.


Although analog stepper driver for sale are typically less expensive than digital ones, the controller often is integrated into the digital drive, which can reduce overall system cost. Analog drives are also easier to set up, with DIP switches being set rather than having to program the parameters so initial motion profiles can be generated quickly. However, digital drives offer more parameter variations, which lets system designers have more options.

Stepper motor types and operation

Tuesday, September 18, 2018

3X MOTION Hybrid Stepper Motors NEMA 24 For Medical USE

3X MOTION Hybrid Stepper Motors NEMA 24 For Medical USE

3X MOTION Hybrid Stepper Motors NEMA 24 For Medical USE


Description                          
                           
3X MOTION Hybrid Stepper Motors SALE are widely used in laboratory and medical equipment, printing machines, pumps vending machines and a multitude of other applications.                          
                           
Customization Options                          
                           
Custom Shaft & Mounting Details:

All NEMA 24 motors can be supplied with single or double ended shaft to customer request shaft length and other dimensions can also be modified on demand.

Number of Leads:

All motors can be supplied with 4, 5, 6 or 8 leads and if required a connector can be provided on our motors to customer request

Winding code:

Since each customer request can be different, we list only our standard products in this catalogue. However, we will be happy to quote other variants to your request.

Holding Torque:

Holding torque is measured with two phases supplied at the rated current. The enclosed technical specifications are therefore typical.
(On customer request for special shaft, leads, fixings, etc. We will provide you with a unique product code/identifier)

Applications:

  • security, 
  • textile, 
  • medical, 
  • 3D printing, 
  • communication,
  • solar etc.

Saturday, September 8, 2018

Advantages and disadvantages of stepper motors

Advantages:
1. Step angle of stepper motor is proportional to pulse rate.
2. Stepper motor outputs its maximum torque at the moment it stops running (when winding excitation).
3. the precision of every step is controlled within the range from 3% to 5%. Plus, the error in the last step won’t be accumulated intothe next step; the stepper motor has very good position precision and good movement repeatability.
4. Excellent start-stop and reversing responses.
5. As stepper motors are brushless ones, the lifetime of stepper motor is determined by the bearings' lifespan only.
6. The response of the motor is only determined by the digital input pulse. Therefore, open-loop control can be adopted. So, theconfiguration of stepper motors can be comparatively simple. The manufacturing cost is low.
7. Synchronous rotation at ultra-low speed can be actualized when the load is coupled with the shaft of stepper motor.
8. As the speed is proportional to the pulse rate, a wide speed range can be avaliable.

Disadvantages:
1. Once stepper motor is out of control or under inappropriate control, resonance is apt to be generated.
2. Comparative high speed is not easy to be achieved.
3. Comparative high torque is not easy to be achieved either.
4. Stepper motor has no advantages in aspects of size and weight. Energy utilization ratio is comparatively low.
5. When overloading, the synchronization will be broken. Vibration and noise occur when running at high speed.

 Source:https://www.oyostepper.com/article-1085-Advantages-and-disadvantages-of-stepper-motors.html

Torque vs Speed Characteristics of Steping Motor

The Speed-Torque graph indicates the characteristic relationship between the speed and torque when the stepping motor is driven. The torq...