Thursday, December 13, 2018

What is pole count of stepping motor?

Simply defined, a pole is a north or south magnetic field of force that is generated by a permanent magnet or current passing through a coil of wire. For stepper motors, however, this definition does not necessarily translate to a simple definition of pole count. Different manufacturers use different names to refer to their poles and various stepper-motor types have varying kinds and numbers of poles.

The motor drive energizes stator teeth one after the other to make the rotor turn, thanks to its magnets’ tendency to force alignment with the stator teeth.

Permanent-magnet stepper motors online are the simplest. Manufacturers define their pole count by the number of pole pairs or stator windings. Increasing the number of pole pairs on the rotor itself (or adding more stator phases) increases resolution. Most permanent-magnet steppers have a resolution of 30° to 3° per step.

Variable-reluctance and hybrid stepper motors have teeth on their rotors, and stators define pole count. These types of stepper motors move 1.8° or less per step.

• For variable reluctance, the more teeth, the greater pole count, the greater the resolution. Rotation step angle is half that of a permanent-magnet stepper motor with the same number of stator windings.

• In contrast, hybrid stepper motors have rotors covered by two radial sections (cups) of magnetized teeth, with a gap in between them. The two cups have teeth that are offset by one tooth in relation to the other. Here too, the greater number of teeth, the greater number of poles, the higher the resolution and the smaller the steps. This means it can rotate a very small amount (See FAQ: What are hybrid stepper motors?) because of its pole count.

This can influence design decisions in a few ways. Basically, the more poles, the more precisely a drive can control stepper motor output. Beyond this simple fact, manufacturers offer varying arrangements and numbers of stator poles and teeth. Designers must consider the application’s required precision, pole and teeth count, design speed, torque, acceleration, and other parameters. Because pole count affects torque as well, it can lead to design decisions related to inertia matching as well (For more on inertia matching, see FAQ: How do stepper motors handle inertia mismatch?) One last note: because the angle of step affects motor vibration and noise, designers should keep that motor feature in mind when making decisions about pole count.

Tuesday, December 11, 2018

How to Control a Stepper Motor with Your Muscles

Background
Designed and written by José Enrique López Pérez, student of Electronic Engineering in Oaxaca, Mexico.

Where can we find a stepper motor? Instead of buying one, you can also get a stepper motor by opening up an old printer. These motors are generally used in devices controlled by digital systems, like robotics, automation, and, of course, our favorite, 3D printers!

How to Control a Stepper Motor with Your Muscles


What are advantages of Stepper motors?() The axis of a stepper motor rotates at regular intervals instead of doing it continuously like DC (direct current) motors. A Stepper Motor is programmed by a micro controller and can be used for precise positioning within a wide range of applications. Precise positioning of a DC motor is not possible by simple methods.

How does a stepping motor work? The stepper motor is known for its ability to convert a train of input pulses (typically square wave pulses) applied to its coils, into a precisely defined increment of movement in the shaft's position. Each pulse moves the shaft through a fixed angle. This is called a step, hence the name stepper motor. The result of this movement is fixed and repeatable, allowing accurate and reliable positioning.

Why are there so many cables in a Stepper Motor? Unipolar Stepper motors can have 5, 6 or 8 terminals that connect to magnetic coils that allow precise positioning, in addition to other cables such as power and ground.

Circuit of Stepper Motor

How to Control a Stepper Motor with Your Muscles



How is a Stepper Motor different from a DC Motor?

A DC (direct current) motor moves continuously, without steps. It´s used when its important to continually regulate the velocity of a motor. These are the common motors you find in radiocontrol cars and other toys.

A DC motor has two terminals, (+) and (-). Electric current is generated through this terminals making the motor spin in a determinate direction.

How to Control a Stepper Motor with Your Muscles


What are the acceleration requirements of step motor?


Wednesday, December 5, 2018

What is the diagram of a stepping motor?

A best stepper Motor for sale is basically a synchronous Motor. In stepper motor there is no brushes. This motor does not rotate continuously, instead it rotates in form of pluses or in discrete steps. Thats why it is called stepper motor.
The principle of Working of stepper motor is Electro-Magnetism.
The Stepper Motor is of following types:
  • Permanent Magnet
  • Variable Reluctance
  • Hybrid Stepper Motor
1.Permanent Magnet Stepper motor
2.Variable Reluctance Stepper motor
3.Hybrid Stepper Motor

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...