How stepper motor works?

Answer 1

Stepper motor
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Go to the site for pictures (On the Right Side).
http://en.wikipedia.org/wiki/Stepper_motor


The top electromagnet (1) is charged, attracting the topmost four teeth of a sprocket.



The top electromagnet (1) is turned off, and the right electromagnet (2) is charged, pulling the nearest four teeth to the right. This results in a rotation of 3.6°.



The bottom electromagnet (3) is charged; another 3.6° rotation occurs.



The left electromagnet (4) is enabled, rotating again by 3.6°. When the top electromagnet (1) is again charged, the teeth in the sprocket will have rotated by one tooth position; since there are 25 teeth, it will take 100 steps to make a full rotation.



Because of induction of the windings, power requirements, and temperature management some glue circuitry is necessary between digital controller and motor.



Different details of configuration have to be decided when choosing a motor. Almost everything is combineableA stepper motor is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps, for example, 200 steps.

This is achieved by increasing the numbers of poles (on both rotor and stator), taking care that they have no common denominator. Additionally, soft magnetic material with many teeth on the rotor and stator cheaply multiplies the number of poles (reluctance motor). Like an AC synchronous motor, it is ideally driven by sinusoidal current, allowing a stepless operation, but this puts some burden on the controller. When using an 8-bit digital controller, 256 microsteps per step are possible. As a digital-to-analog converter produces unwanted ohmic heat in the controller, pulse-width modulation is used instead to regulate the mean current. Simpler models switch voltage only for doing a step, thus needing an extra current limiter: for every step, they switch a single cable to the motor. Bipolar controllers can switch between supply voltage, ground, and unconnected. Unipolar controllers can only connect or disconnect a cable, because the voltage is already hard wired. Unipolar controllers need center-tapped windings.

Typically a bipolar stepper motor has 4 wires coming out of it. Each pair of wires is connected to the ends of two coils. The wires must be toggled between ground and voltage, which is usually accomplished via a set of transistors. Unipolar stepper motor has 5 or 6 wires. The extra wires are referred to as "common." They are located in the middle of the two coils and consistently supply voltage to the coils. The 4 wires that are located at the ends of the coils now switch between unconnected and ground. This helps reduce number of transistors required in the circuit. One way to distinguish common wire from a coil-end wire is by measuring the resistance. Resistance between common wire and coil-end wire is always half of what it is between coil-end and coil-end wires. This is due to the fact that there is actually twice the length of coil between the ends and only half from center (common wire) to the end.

It is possible to drive unipolar stepper motors with bipolar drivers. The idea is to connect the output pins of the driver to 4 transistors. The transistor must be grounded at the emitter and the driver pin must be connected to the base. Collector is connected to the coil wire of the motor.

Stepper motors are rated by the torque they produce. Synchronous electric motors using soft magnetic materials (having a core) have the ability to provide position holding torque (called detent torque, and sometimes included in the specifications) while not driven electrically. To achieve full rated torque, the coils in a stepper motor must reach their full rated current during each step. The voltage rating (if there is one) is almost meaningless. The motors also suffer from EMF, which means that once the coil is turned off it starts to generate current because the motor is still rotating. There needs to be an explicit way to handle this extra current in a circuit otherwise it can cause damage and affect performance of the motor.

Answer 2

Stepper Motors, or as otherwise called Step Motors are classified as a brushless DC motor but as such do not operate that way. They are more akin to Synchronous AC motors. Just applying a DC voltage to one of its coils will not cause it to rotate (well maybe a small lurch); so for operational purposes we need to consider what actually causes the shaft to rotate. In a Stepper Motor both the Stator (Field) and the Rotor (armature) have “Teeth”. These teeth form poles of the magnetic field. The rotating armature is constructed of multi pole permanent magnets while the Stator is constructed of coils around shaped steel laminations. As a current is applied to a coil, the field causes a set of stator & rotor teeth to align and the shaft moves. NEMA 14 Stepper Motors Another pulse to the same coil does not produce anything as the poles are already aligned. So now we come to the second set of coils! Oh yeah, forgot mention that there is a difference in the number of poles or that there are 2 sets (sometimes more) of rotor magnets offset from each other! Now that we have cleared that up, we now have 1 coil set & 1 Magnet set aligned. Well the other set is now misaligned. By now pulsing the second set, the rotor will now move into alignment with the next set of poles.

The rotor will rotate, 1 “lurch” at a time. We call this “Jump or Lurch” a Step! The number of steps is determined by the pole sets. 360/steps = the angle turned each step. So 200 step/1 rotation=1.8deg./step OR a 1.8deg. stepper requires 200 pulses to make 1 revolution. We can force the motor to make a “Half” or other step sizes by careful sequence and polarity of how we energize the coil sets.


https://www.electrikals.com/

Answer 3

A stepper motor is in basic terms a motor which turns by ability of discrete steps somewhat than a gentle action. think of an eternal magnet on a shaft with a set of coils spaced in a circle. If I energize one set of coils, the magnet will line up with that coil set. Then, I de-energize that set and energize the subsequent set inflicting the magnet to now align with the subsequent set of coils and so on. as long as I sequence from one set of coils to the subsequent, the magnet maintains to maintain on with the magnetic field from one step to the subsequent, for this reason the call of stepper motor because of the fact it strikes in discrete .steps, one by one If I try this sequence speedy sufficient, the action will become smoother and smoother and much less like discrete steps. Stepper autos are smart as a positioning gadget for the reason which you could end the motor at any element and the magnetic field then acts like a brake to hold the shaft in a fixed place. the pinnacle in a floppy or no longer difficulty-free disk is placed with a stepper motor which turns a screw. an actual style of steps from a reference element places the pinnacle in precisely the comparable place every time. without the flexibility to step, that's totally confusing to return to an actual place to align with the magnetic music on the disk media. in case you % extra information, use your renowned seek engine and a few properly chosen keywords...

Answer 4

http://www.motioncontrolguide.com/learn/guides/stepper-motor-guide/
I hope this helps