Latest News

How to Choose Best Closed Loop Stepper Motors Right for You

Published

5 years ago

January 24, 2020

Sebastian

CNC blog readers often ask me how to design a stepper motor and choose which to apply now. What are the most important criteria when choosing a stepper motor?

Anyone who has ever purchased a Closed Loop Stepper Motors knows that there are many stepper motors in various designs, sizes, and performance classes on the market. You can easily track things without proper setup and stand in front of an array of engines like the ideal “Ochs vorm Berg”.

But do not panic! Closed Loop Stepper Motors design and selection is not rocket science either. You just must keep a few simple things in mind. In this article, I will give you the best advice for designing and selecting stepper motors. Here you will learn:

What kinds of stepper motors are there?
What are the main characteristics of the stepper motor?
How to calculate the required performance data from your application

Well, fresh to work. Do not waste time and read quickly!

Table of Contents

Toggle

What types of stepper motors are available?

A Closed Loop Stepper Motors is a motor, which can be seen mechanically, to perform a single partial revolution – one step – by appropriate control. Many steps together lead in turn. You can see a nice animation on Nanotec. In principle, stepper motors are divided into the following three designs:

1.Closed Loop Stepper Motors frequency

In the impedance stepper motor, the rotor is designed without winding copper and without magnet. This rotor is made of soft magnetic material (fine iron) and has small teeth in its vicinity.

If you turn this operating shaft in the off state, you will not notice any resistance or lock.

When the stator is activated, the field lines pass through the soft magnetic rotor. Since field lines find a shorter path back to the stator through the teeth, the force acts on the rotor leading to its rotation and nutone replacement fans. By intelligently activating the stator, the rotor is always rotated step by step.

Due to the sophisticated control electronics and the lack of self-locking (no magnets!), Frequency drives are only suitable for specialized applications.

2.Permanent magnet stepping motor

The permanent magnet stepper motors usually have a stator with two winding threads (4 connections). The rotor is equipped with a permanent magnet. If you turn this Closed Loop Stepper Motors that is turned off and unplugged, you can feel sudden dizziness. The lock is noticeable due to the north-south magnet on the rotor.

The most common version is the so-called Closed Loop Stepper Motors clutch pole. Due to its simple design, the pole clutch Closed Loop Stepper Motors is the cheapest type of Closed Loop Stepper Motors on the market. Clutch stepper motors, however, have defects of step size and torque compared to hybrid stepper motors.

3.Hybrid stepper motor

Hybrid stepper motors combine the advantages of frequency drives and permanent stepper motors. In the case of motors with a hybrid stepper, a permanent magnet is placed on the rotor. At the same time, two soft sprockets are placed, half of which are offset. In this design, the hybrid Closed Loop Stepper Motors achieves higher torque with the most accurate splitting of steps. Almost all stepper motors that you can buy currently on the market are hybrid stepper motors.

The most important characteristics of the stepper design are …?

To distinguish between stepper motors, you must know what is especially important:

Torque and torque hold

Torque is one of the most important criteria when choosing a stepper motor. Since the torque is largely dependent on the speed, there is also a fixed or suspended torque. This indicates what the engine can do in a deadlock.

Step angle and number of steps in the revolution

For each stepper motor, the step angle is indicated on the board or on the datasheet. For example, a step angle of 1.8 degrees means that the engine makes one complete revolution in 200 steps. (1.8 ° * 200 = 360 ° == one cycle)

By controlling the Closed Loop Stepper Motors with split half, quarter, or eighth, you can improve screen resolution. Before buying, you should think exactly how to position you with a stepper motor.

Number of stages and types of communication

The Closed Loop Stepper Motors can be connected as follows:

Do not eavesdrop on money
Tap center
Common eavesdropping

Closed Loop Stepper Motors with 4-phase connections is usually a bipolar stepper motor. This means that the current is transmitted during one stage in one direction and in the other (the poles = two poles).

The six-link Closed Loop Stepper Motors is usually a unipolar stepper motor, but under certain conditions, it can also be controlled by a dipole.

Inductance and resistance coils

Now he is getting electricity. To ensure that the engine also reaches the nominal power or nominal torque specified on the board, you must supply it with a voltage source. The mains supply must be able to provide corresponding high currents without voltage drop. Closed Loop Stepper Motors controllers work with the current control, so you don’t have to worry about the current.

Attention, stepper motors can be connected in series and in parallel. I will add more to this and choose the power source at this point.

The current maximum stage

The current stage or the current stage specified in the datasheet or nameplate should not be overridden. Otherwise, the Closed Loop Stepper Motors may overheat and fail.

Mechanical connection

The Closed Loop Stepper Motors flange dimension is usually standardized according to NEMA (National Association of American Electrical Appliance Manufacturers). The most common sizes are Nema 17 (aperture pattern 42 x 42), Nema 23 (aperture pattern 56 x 56) and Nema 42 (with an aperture pattern of 86 x 86 for connected flange).

You can easily use the drive shaft for Closed Loop Stepper Motorseg peer connection using Rotex coupling. These joints with a plastic fixation have proven themselves in practice as they dampen vibrations and shocks well.

Position and angle of measurement

All cheap and common stepper motors have no built-in angle or speed sensor. In the Standard Edition, stepper motors are “initially” only suitable for control tasks.

To format drive 0’s position when turning on the device, you must first manipulate a reference key while running an exact reference. The zero position is determined by the reference range. Since you control the Closed Loop Stepper Motors with a specified number of steps, you can easily calculate how many steps the Closed Loop Stepper Motors should move from the reference point.

The disadvantage of this type of position measurement is that the step overload occurs when the motor is overloaded, which causes the calculated position to be invalidated.

If you need high accuracy GPS positioning and repetition or a control ring in your application, you should also integrate the rotation angle sensor or position sensor into the drive assembly.

I did, as far as gray theory! But how do I design the right Closed Loop Stepper Motors now?

This is how you calculate the required performance data from your application

Calculation of a Closed Loop Stepper Motors for a direct rotary motor

At this point, the required torque for the Closed Loop Stepper Motors is given directly from your application. You just must think about whether the torque needs additional increment in order to achieve a certain acceleration or acceleration time.

Calculation of stepper motors for helical gear

If you are using a Closed Loop Stepper Motors to drive a screw gear (like a trapezoidal screw, ball screw, threaded rod, etc.), i.e. converting the rotational motion of the Closed Loop Stepper Motors into a linear motion, you can use the following thumb base:

Given:

Spindle pitch r

Linear travel speed v_min is required

The driving force required for the gear in an axial direction F_min

search:

The minimum speed required for a Closed Loop Stepper Motorsn_min = v_min / p

Minimum torque required for Closed Loop Stepper Motors M_min = (F_min * p) / (2 * pi)

For example, in order to determine the driving force needed for a CNC milling table, the maximum cutting force that occurs for the required driving force in the axial direction can be used. Because the bottom line should have at least the power to transfer the power of the chips.

Calculate the chip forces for the most difficult cutting and use it in the above formula to determine the torque required for a stepper motor. In this article, you will learn more about calculating cutting forces when grinding.

Of course, you also must include protection. Otherwise, you will not be able to grind properly as drive friction increases. I would cautiously suggest a safety factor of 2 at this point so that the specified Closed Loop Stepper Motors torque is two times higher than the calculated torque. Additional torque also helps to accelerate the linear table if high dynamics are required.