Which Has Higher Stopping Accuracy - Stepper Motor or Servo Motor?

Customer Inquiry: Looking for a motor with good stopping accuracy. How much of a difference is there between stepper motors and servo motors?

Assumption: The AC servo motor NX Series is equipped with a 20-bit encoder, thus it should have a fine resolution, and good stopping accuracy.

First, it is necessary to clarify the difference between resolution and stopping accuracy: Resolution is the number of steps per revolution and it is also called a step angle for stepping motors. It is needed when considering how precise the required positioning needs to be. Stopping accuracy is the difference between the actual stop position and theoretical stop position.

Does this mean that the AC servo motor equipped with a high accuracy encoder has better stopping accuracy than hybrid step motor?

Not quite. In the past there was no issue with the concept of "stopping accuracy of servo motors being equal to encoder resolution within ±1 pulse." However, recent servo motors are equipped with the 20 bit encoder (1,048,576 steps) which has a very fine resolution. Because of this, errors due to the encoder installation accuracy have a huge effect on stopping accuracy. Therefore, the concept of stopping accuracy has slightly started to change.

Source:
http://obd2newsfrance.blogspot.com/2018/06/basics-of-stepper-motors-you-should-know.html

Some differences between bipolar and unipolar stepper motor

A bipolar stepper motor for sale has one winding per stator phase. A two phase bipolar stepper motor will have 4 leads. In a bipolar stepper we don’t have a common lead like in a uni-polar stepper motor. Hence, there is no natural reversal of current direction through the winding.

A bipolar stepper motor has easy wiring arrangement but its operation is little complex. In order to drive a bipolar stepper, we need a driver IC with an internal H bridge circuit. This is because, in order to reverse the polarity of stator poles, the current needs to be reversed. This can only be done through a H bridge.



Bipolar Stepper Drives
Many companies have started assembling their own bipolar stepper drives. Care must be taken that you connect the stepper motor correctly to the drive. Also the drive must be able to supply sufficient current for you stepper. The micro-controller must only provide the step and direction signal to the drive. This method will occupy only two micro-controller pins and is very helpful in projects that require large number of micro-controller pins for other functions.



Unipolar Stepper v/s Bipolar Stepper
Both bipolar steppers and unipolar stepepr motor for sale are used widely in projects. However, they have their own advantages and disadvantages from the application point of view. The advantage of a uni-polar motor is that we do not have to use a complex H bridge circuitry to control the stepper motor. Only a simple driver like ULN2003A will do the task satisfactorily. But, there is one disadvantage of uni-polar motors. The torque generated by them is quite less. This is because the current is flowing only through the half the winding. Hence they are used in low torque applications. On the other hand, bipolar stepper motors are a little complex to wire as we have to use a current reversing H bridge driver IC like an L293D. But the advantage is that the current will flow through the full coil. The resulting torque generated by the motor is larger as compared to a uni-polar motor.

Source:https://www.oyostepper.com/article-1076-Some-differences-between-bipolar-and-unipolar-stepper-motor.html

Are you searching for the best electronic equipment at a reasonable rate?

Are you searching for the best electronic equipment at a reasonable rate? Great! Do you know the right type of equipment to get started? If no, need not worry! Web shopping portals feel delighted to get you introduced to some exclusive collections. Rather than hovering to and fro, you may get the best within a few clicks at the comfort of your home.

Online shopping has now become a common trend due to numerous benefits in the association. Buying the best BLDC Motor is preferable due to a large range of collections along with justified price and ease. These equipment are a bit costly due to which purchasing them from reliable online dealers will give you the best output.

Cost Along with Size – Vital Point to Take into Consideration

Cost along with size and functionality are some of the vital things that need to be looked at the time of making an online purchase of electronic gadgets. In case you are searching for something great comprising of numerous functionalities, then you need to pay a bit high and vice versa. The one available with little functionalities may be availed at rock bottom price list. 

Better to go through online classified sites to get into touch with numerous and variable types of items. There is also a possibility that you may get in touch with great deals which will really prove to be highly beneficial. Next comes the turn of size! The selection of size must be done by a number of people for whom you will be cooking. 

Why Decide the Size in a Precise Manner?

People prefer going with motors belonging to gigantic sizes. Also, medium-sized motors have gained high popularity. Functionality is another vital thing that needs to be kept into high consideration. Some of the features that need to be looked after include the following:

• Easy repairing
• Availability of parts
• Efficiency
• Flexibility

Better to conduct an online survey to get to know more about the same in detail. There are numerous tips by experts that have been aired for the convenience of users. You need to ensure that these tips along with functionalities may be into usage in actual usage rather than sounding soothing. Such vital pieces of information will let you make the right type of selection.

Purchasing of an Optical Encoder from a Reliable Supplier

Whether online or offline, it is recommended to shake hands with a reliable supplier to make the best use of your hard earned investment. If you are planning to purchase the most suitable stepper motor with encoder

, then you must approach the most trustworthy supplier. You may get in touch with a trustworthy supplier online by:

• Visiting the World Wide Web in a thorough manner
• Going through reviews that have been posted by previous clients
• Getting in touch personally with the supplier

The supplier hesitant to open up all details in a broad manner must be abandoned completely. Following these vital tips will let you get in touch with the right type o item online without any difficulty.

TWO DIMENSIONS OF Linear Stepper Motor

We’ve all heard linear motors, like those propelling Maglev trains, described as “unrolled” versions of regular electric motors. The analogy is apt and helps to understand how a linear motor works, but it begs the question: what if we could unroll the stator in two dimensions instead of just one?

That’s the idea behind [1.8 deg stepper motor] two-axis stepper motor, which looks like it has a lot of potential for some interesting applications. Build details are sparse, but from what we can gather from the videos and the Hackaday.io post, [BetaChecker] has created a platen of 288 hand-wound copper coils, each of which can be selectively controlled through a large number of L293 H-bridge chips and an Arduino Mega. A variety of sleds, each with neodymium magnets in the base, can be applied to the platen, and depending on how the coils are energized, the sled can move in either dimension. For vertical applications, it looks like some coils are used to hold the sled to the platen while others are used to propel it. There are RGB LEDs inside the bore of each coil, although their function beyond zazzle is unclear.

We’d love more details to gauge where this is going, but with better resolution, something like this could make a great 3D-printer bed. If one-dimensional movement is enough for you, though, check out this linear stepper motor for sale that works on a similar principle.

Stepper Motor Control by Varying Clock Pulses

Stepper motor online control circuit is a simple and low-cost circuit, mainly used in low power applications. The circuit is shown in figure, which consist 555 timers IC as stable multi-vibrator. The frequency is calculated by using below given relationship:

Frequency = 1/T = 1.45/(RA + 2RB)C Where RA = RB = R2 = R3 = 4.7 kilo-ohm and C = C2 = 100 µF.

The output of timer is used as clock for two 7474 dual ‘D’ flip-flops (U4 and U3) configured as a ring counter. When power is initially switched on, only the first flip-flop is set (i.e. Q output at pin 5 of U3 will be at logic ‘1’) and the other three flip-flops are reset (i.e. output of Q is at logic 0). On receipt of a clock pulse, the logic ‘1’ output of the first flip-flop gets shifted to the second flip-flop (pin 9 of U3). Thus logic 1 output keeps shifting in a circular manner with every clock pulse. Q outputs of all the four flip-flops are amplified by Darling-ton transistor arrays inside ULN2003 (U2) and connected to the stepper motor windings orange ,brown, yellow, black to 16, 15 ,14, 13 of ULN2003 and the red to +ve supply.

The common point of the winding is connected to +12V DC supply, which is also connected to pin 9 of ULN2003. The color code used for the windings is may vary form make to make. When the power is switched on, the control signal connected to SET pin of the first flip-flop and CLR pins of the other three flip-flops goes active ‘low’ (because of the power-on-reset circuit formed by R1-C1 combination) to set the first flip-flop and reset the remaining three flip-flops. On reset, Q1 of IC3 goes ‘high’ while all other Q outputs go ‘low’. External reset can be activated by pressing the reset switch. By pressing the reset switch, you can stop the stepper motor. The motor again starts rotating in the same direction by releasing the reset switch.

Now you have got an idea about the types of super high torque stepper motor
 and its applications if you have any queries on this topic or on the electrical and electronic projects leave the comments below.

Three Major Types of Stepper Motor

Three types of stepper motors are in common use today: Permanent magnet, variable reluctance, and hybrid. Of these, hybrid steppers are by far the most popular – they combine the high points of the other two designs using multi-toothed stator poles and a permanent magnet rotor.

No matter the type of stepper motor including nema 17 stepper motor, engineers should be familiar with the three step modes:

Full Step
With 200 total rotor teeth, full step mode is the equivalent of a 1.8-degree full step angle. When the motor is operating as intended, one digital pulse from the device’s driver is equal to one step. Typically, both windings are energized while the current is reversed alternately.

Half Step
In half step mode, the motor rotates at a full 400 steps per revolution. The step angle is .9 degrees, half the amount of full step. This is ideal for producing smoother motion at the expense of a noticeable, though not severe, reduction in torque.

Microstep
A relatively new innovation, microstep mode can subdivide a complete step into 256 microstep. This means a complete revolution is an astonishing 51,200 steps—enhancing positional accuracy and smoothness over a wider variety of speeds.

Stepper Motors 101: How Do They Work?

Construction of Hybrid Stepper Motor

The stator of this stepper motor is same as its permanent magnet or reluctance type counterpart. The stator coils are wound on alternate poles. In this, the coils of different phases are wound on each pole, usually two coils at a pole which is referred as a bifilar connection.

The rotor consists of a permanent magnet which is magnetized in axial direction to create a pair of magnetic poles (N and S poles).  Each pole is covered with uniformly spaced teeth. The teeth are made up of soft steel and two section, of which on each pole are misaligned each other by a half-tooth pitch.

Working of Hybrid Stepper Motor:

This motor works similar to that of permanent magnet stepper motor. The figure above shows 2-phase, 4-pole, 6-tooth rotor hybrid stepper motor. When the phase A-A’ is excited with a DC supply, keeping B-B’ unexcited, the rotor aligns such that the south pole of the rotor faces north pole of the stator while north pole of rotor faces south pole of the stator.

Now, if the phase B-B’ is excited, keeping A-A’ switched off in such a way that upper pole becomes north and lower becomes south, then the rotor will align to a new position by moving through counterclockwise direction. If the phase B-B’ is oppositely excited such that the upper pole becomes south and lower becomes north, then the rotor will turn clockwise direction.

By a proper sequence of pulses to the stator, the motor will turn in desired direction. For every excitation, rotor will get locked into new position, and even if excitation is removed motor still maintains its locked condition due to the permanent magnet excitation. The step angle of this 2-phase, 4-pole, 6-tooth rotor motor is given as 360/ (2 × 6) = 30 degrees. In practice, hybrid motors are constructed with more number of rotor poles in order to get high angular resolution.

 What is a Stepper Motor Used for?

FAQ of Stepper Motor and Driver - Oyostepper.com