Posts Tagged 'Stepper Motor'

New 20mm Linear Stepper Motor now available from Nippon Pulse

RADFORD, Va. – Nippon Pulse is excited to introduce its smallest linear stepper motor yet, the PFL20 Linearstep. The PFL20 is a highly efficient, high thrust tin-can linear actuator with a 20mm diameter and a bipolar winding.

PFL20 is RoHS-compliant, has a 30/60mm effective stroke, and can reach 6 N of force at 200 pps. With 24 steps per revolution, the lead screw has a 1.2mm thread pitch; the PFL20 also reaches 5V rated voltage, resistance of 33 Ohms/phase and inductance of 12mH/phase. The datasheet with additional specifications can be found here.

The simple structure of Linearstep motors – just a threaded rotor hub and lead screw – helps to save space and reduce costs, due to fewer components needed compared to systems that convert rotary motion to linear. Linearstep motors are also easy to control, and can be ordered with unipolar or bipolar windings and a variety of usable voltages. In addition to the 20mm motor size, this motor is also available in 25mm (captive or non-captive option) and 35mm diameter sizes.

Nippon Pulse’s tin-can linear actuators, including the Linearstep, are also available for customization; contact an applications engineer to learn more about our customization capabilities.

Information on the PFL20 from Nippon Pulse can be viewed at:

https://www.electromate.com/assets/catalog-library/pdfs/nippon-pulse/Nippon_Pulse_pfl20_specsheet.pdf

For further information, please contact:

EDITORIAL CONTACT:
Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

 

Tags:  Linear Step Motor, PFL20, Stepper Motor, Electromate, Nippon Pulse

A Primer on Stepper Motors

A Step Motor is a motor with windings in the stator and permanent magnets attached to the rotor. It provides fixed mechanical increments of motion; these increments are referred to as steps and are generally specified in degrees. A step motor, in conjunction with a stepper drive, rotates in predefined angles proportional to the digital input command (stepper) pulses. A typical full-step system achieves 200 steps per revolution, this equates to 1.8º per full step.

STEPS/REVOLUTION

Steps per revolution equals 360° divided by step angle (0.9°, 1.8°, 3.75°, 7.5° and 15°) when the motors are driven in full-step excitation mode.

0.9° = 400 steps/rev
1.8° = 200 steps/rev
7.5° = 48 steps/rev
15° = 24 steps/rev

ADVANTAGES/DISADVANTAGES

There are several advantages of using stepper motors.  Step motors provide acceleration torque equal to running torque and require no maintenance.  Speed can easily be determined and controlled by remembering speed equals steps per revolution divided by pulse rate.  Stepper motors can also make fine incremental moves and do not require a feedback encoder (open loop). Stepper motors also have fast acceleration capability and have non-cumulative positioning error. Along with excellent low speed/high torque characteristics without gear reduction, stepper motors can also be used to hold loads in a stationary position without creating overheating.

Disadvantages of step motors include: loss of synchronization resulting position error, resonance affecting motor smoothness, limited operation at high speeds, running hot, and can stall with excessive loads.

TYPES OF STEPPER MOTORS

Variable Reluctance:  Has teeth on the rotor and stator but no rotor permanent magnet.

Permanent Magnet:  Has a permanent magnet for a rotor but no soft iron rotor teeth.  Permanent magnet step motors can be subdivided into ‘tin-can or can-stack’ and ‘hybrid’, tin-can (can-stack) being an inexpensive version, and hybrid versions constructed with higher quality bearings, smaller step angle and higher power density.

Hybrid Synchronous:  Combines the magnet from the permanent magnet motor and the rotor and stator teeth from the variable reluctance motor.

ROTARY OR LINEAR STEPPER MOTORS

Step motors can be linear or rotary.  Electromate® offers a full line of low-cost short-delivery hybrid rotary step motors from sizes NEMA 8 to NEMA 42, including IP65 rated step motors and stepper gearmotors.  Electromate®‘s step motors are available in 4, 6 & 8 lead configurations for bipolar or unipolar operation, and can be wired in series or parallel.  All our step motors have optional rear shaft extensions, encoders and gearboxes.

Linear Step Motors are also known as Step Motor Linear Actuators, and have a threaded rod/acme screw in place of a smooth shaft.  Linear step motors provide a simple motion system at a fraction of the cost of conventional rotary stepper motors and traditional linear motion systems.  Linear step motors offers a wide range of customizable options, including various screw pitches, screw lengths, bipolar or unipolar windings, and several operating voltages.

CLICK HERE to view Electromate’s full family of Stepper Motors.

For more information, please contact:

EDITORIAL CONTACT:
Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
http://www.electromate.com

 

Tags:  Step Motor, Stepper Motor, Rotary Step Motor, Linear Step Motor, Step Motor Linear Actuator, Variable Reluctance Motor, Hybrid Synchronous Motor,  Permanent Magnet Motor, Electromate

New Integrated StepSERVO™ Motors from Applied Motion Products

Integrated Step Motors fuse step motor plus drive and control components into a single device. Integrated steppers offer a space-saving design that reduces wiring and saves on cost over separate motor and drive components.

AMP INTEGRATED MOTOR FAMILY

Ideally suited for applications such as packaging and labeling, automated test and measurement, automated assembly and life sciences, StepSERVO™ motors from Applied Motion Products provide the next evolution integrated step motor technology. Starting with a proven integrated motor design, we add a high-resolution incremental encoder and closed-loop servo firmware to create a motor that offers the best step motor performance available today. StepSERVO™ motors offer the same high-torque-at-low-speed and excellent holding torque characteristics of open loop stepping motors with the advantages of true closed-loop control. These advantages include the ability to create peak torques from the motor up to 50% higher than the normal torque range of the same step motor running open loop. Closed-loop also means the motor only draws current when it needs it, so step motors now run cooler than ever before.  StepSERVO™ motors feature:

  • NEMA frame size 17, 23 and 24. StepSERVO motors utilize 5000 line incremental encoders (20,000 counts/rev)
  • NEMA frame size 11. StepSERVO motors utilize 1024 line incremental encoders (4,096 counts/rev)
  • Closed-loop servo control using high torque step motors
  • High acceleration for faster machine cycles and greater productivity
  • Energy efficient, cool running
  • All-in-one compact solution
  • IP65 versions for wet and dusty environments
  • Stand-alone operation (stored Q programming)
  • EtherNet/IP industrial networking option
  • CANopen fieldbus option
  • Modbus RTU option for easy PLC/HMI connection

Click on the following link to view a 30minute YouTube Video on the StepSERVO™ integrated stepper motor.

There are three types of StepSERVO™ to choose from:

SSM integrated steppers feature:Applied Motion Products SSM23IP-3EG

  • NEMA 23 frame size motors
  • Ethernet (RJ-45) port for programming
  • EtherNet/IP industrial networking standard
  • Three motor lengths (stack lengths) available to provide the highest amount of torque in the shortest motor possible

 

TSM integrated steppers feature:

  • NEMA 11 (New!), NEMA 17 and NEMA 23 frame size motors
  • RS-232 or RS-485 port for programming and streaming commandsApplied Motion Products TSM11-1
  • Control options including CANopen fieldbus control, digital step & direction control, analog velocity mode, streaming commands and stand-alone operation using stored Q programs.
  • Three motor lengths available in each frame size to provide the highest amount of torque for each length

 

TXM integrated steppers feature:

  • IP65 rated for wet and dusty environmentsApplied Motion Products TXM24C-3CG
  • NEMA 24 frame size motors
  • RS-232, RS-485 or Ethernet port (M12) for programming, streaming commands and fieldbus/networking
  • Control options include CANopen fieldbus control, EtherNet/IP industrial networking, digital step & direction control, analog velocity mode, streaming commands and stand-alone operation using stored Q programs.
  • Two motor lengths available to provide both a lower torque and a higher torque option depending on application requirements

CLICK HERE for additional information on the StepSERVO™ motors from Applied Motion Products.

Why Does My Step Motor Get Hot? – The Why? Series YouTube Video

New 4 minute YouTube Video

Can my step motor get hot enough to cook an egg?  In this segment of The Why? Series, Bob White, Manager, Training and Digital Marketing at Kollmorgen, explains why a typical step motor may get hot.  Learn why a step motor will heat up, and what can be done to reduce this heating…unless of course, you are looking to cook an egg!

Click on the link below to view this 4 minute YouTube Video.

Tags:  Step Motor, Stepper Motor, Kollmorgen, Electromate

 

This Motor Maker Is Heading Into Space and Killing It

Reprint of 10/25/15 Design News article by Tracey Schelmetic, Contributing Writer

Empire Magnetics Space MotorAs commercial space flight becomes a reality, it has launched a movement to develop industrial systems that will operate in a variety of harsh environments from the intense G-forces of vehicle launches, to zero gravity, to temperatures far beyond those on Earth.  While some of the most urgent problems for motors in space have been largely solved in previous decades — bearings and lubrication issues, in particular – there are new engineering challenges as motors are custom-developed for space applications.  Typical motors are designed for low cost and high manufacturing volume.  For space applications, the precise opposite is true.

Rohnert Park, Calif.-based Empire Magnetics Inc. has a tagline: “Motors that survive.”  The company designed and built some of the momentum controls for the Wake Shield Facility, an experimental science platform that was placed in low earth orbit by the Space Shuttle.  The facility is a 12-foot-diameter free-flying stainless steel disk designed to redirect atmospheric particles around the sides to create an “ultra vacuum” that is used to study epitaxial film growth.

Empire also custom-built and designed an actuator for commercial space flight company Orbital Sciences.  The actuator needed to be exceptionally stiff to be able to operate under the extreme G forces of flight launches.  The company’s solution used a double-ended screw combined with a hollow-shafted motor; it was a design that placed all of the thrust loads on the screw, so the motor needed only enough torque to turn the screw.

Richard Halstead, Empire’s president, in an interview with Design News, noted that the difference between Earth motors and space motors is that the former do not have to take into consideration the selection of materials that will survive vacuum, space radiation, or temperature extremes.  There is also the cost of a motor failure in space.

“The cost of failure for the supplier of a standard industrial motor is typically limited to the cost of a replacement motor,” Halstead told Design News.  “The cost of a failure in space can be exceptionally high.  Due to the steps in the manufacturing process, taking a motor completely apart and reassembling it is not feasible, as there won’t be enough material left to re-establish dimensional tolerances.”

For typical motors, when high reliability is required, designers create mechanically redundant designs.  Mechanical redundancy, however, comes with size and weight penalties that make motors impractical for use in space, and their performance may also be affected.  The inertia of two rotors takes more torque and power to accelerate than does one. Empire believes that the most practical solution is having redundant electrical circuits in the same mechanical motor housing.

Another great challenge, said Halstead, is overcoming the tendency of lubricants, varnishes, and glues to outgas in a vacuum environment.  Traditional motors are made of iron, which is stamped, coated, glued, stacked, and assembled into the basic motor structure, and this can cause serious problems, as can lubricants that are added to reduce tool wear during stamping operations.

“If there is a significant level of outgassing, the material evaporates, and then re-deposits on everything inside the chamber,” Halstead told Design News.  “The bearings can fail for lack of lubrication, while the contamination can fog optics or foul manufacturing processes.”

Temperature is one of the next biggest challenges.  The “thermal shock” of space can see equipment cycle from temperatures of 200°C in direct sunlight to temperatures of -200°C, all in a few seconds.  For spacecraft designed to go further than low Earth orbit, deep space temperatures of 20 Kelvin (-253°C) can be expected.  Warping due to thermal shock can cause mechanical lock-up of the motor, and different material expansions from thermal cycling can also cause motor lock-up. Adapting a traditional motor design for use in space is therefore asking for trouble, according to Halstead.

Typical windings in a brushless motor stator, showing complete slot fill. Redundant design is required for space applications, as a backup in case of component failure. When the engineer decides to have redundant windings, something has to change in terms of motor performance. To preserve performance specs, a better solution to mechanical redundancy is electrical redundancy in the same mechanical housing. (Source: Empire Magnetics)

Typical windings in a brushless motor stator, showing complete slot fill.  Redundant design is required for space applications, as a backup in case of component failure. When the engineer decides to have redundant windings, something has to change in terms of motor performance.  To preserve performance specs, a better solution to mechanical redundancy is electrical redundancy in the same mechanical housing. (Source: Empire Magnetics)

“Metals need to be stress-relieved; otherwise they warp or deform due to the temperature cycling,” he said. “Cold metals become brittle, so this has to be considered when doing strength calculations.  Copper shrinks faster than steel, and epoxy changes dimensions faster than magnetic iron. If these factors are not considered, the motor is likely to fail.”

Even repair processes are fundamentally altered in space applications. While individual components can be replaced on Earth, the nature of space repair – think astronauts in bulky spacesuits with limited visibility and low manual dexterity – means that whole systems must be replaced rather than repaired.  If the motor fails, it will most likely damage the electronics, so it becomes safer to simply replace the whole unit.

To use an Earth analogy, a NASCAR team wouldn’t use the motor of a Ford Escort as the building block for its Indianapolis 500 run, as Halstead puts it, and space researchers shouldn’t use a standard commercial grade motor as the building block for space exploration.

Stepper Motor Primer

Stepper Motors from Electromate

Stepper Motors from Electromate

There are three basic types of step motors: variable reluctance, permanent magnet and hybrid.  A hybrid step motor is a simple low cost means of providing good motion performance.  Step motors are electromechanical devices that work by dividing shaft rotation into discrete distances called steps. Basically, they are brushless motors which include permanent magnet variable reluctance and hybrid types.  Most step motors are hybrids and feature 200 steps per revolution (1.8 degrees). The magnetic structure of the motor is designed to be incremental in nature i.e one pulse to the motor causes the armature to move one complete step.  At power up, a hybrid step motor could rotate up to ±3.6 degrees in either direction due to the rotor having 200 natural detent positions….

Click on the link below to download this complete white paper.

Click to access StepperMotorPrimerv2.pdf

For more information, please contact:

EDITORIAL CONTACT:

Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

 

Tags:  Step Motor, DC Step Motor, Stepper Motor, BLDC Motor, Automation, Motion Control

Stepper Motor Linear Actuators 101

What exactly is a Stepper Motor Based Linear Actuator?

Need to know how a Stepper Motor Linear Actuator works?

Suppose you, as an engineer, are tasked to design a machine or part of a machine that requires precise linear positioning.   How would you go about accomplishing this?  What is the most straightforward and effective method?

Haydon Kerk Stepper Motor Linear Actuator White Paper

Haydon Kerk Stepper Motor Linear Actuator White Paper

When students are trained in classic mechanical engineering, they are taught to construct a system using conventional mechanical components to convert rotary into linear motion.   Converting rotary to linear motion can be accomplished by several mechanical means using a motor, rack and pinion, belt and pulley, and other mechanical linkages.   The most effective way to accomplish this rotary to linear motion, however, is within the motor itself.

This White Paper, from Haydon Kerk Motion Solutions, discusses the technology behind stepper motor linear actuators, what makes them different, and concludes with a detailed example illustrating how they should be sized to move a given load.   Click on the link below to download it.

http://www.electromate.com/db_support/downloads/Stepper_Motor_Linear_Actuators_101v2.pdf

More information on the Haydon Kerk Can Stack Stepper Motor Linear Actuators can be viewed at-

http://www.electromate.com/products/?keyword=Hybrid+Stepper+Motor+Linear+Actuators&d=105216

For more information, please contact:

Electromate Industrial Sales Ltd.
www.electromate.com
sales@electromate.com

Phone:  905-850-7447
Fax:       905-850-7451
Toll Free Phone: 877-737-8698
Toll Free Fax:   877-737-8699

Tags:  Stepper Motor, Step Motor Linear Actuator, Stepper Motor Linear Actuator, Electromate, Haydon Kerk, Step Motor, White Paper

Step Motor Frequently Asked Questions

Q. How hot can we run a step motor without damaging it?

A. The temperature range of our motors is -20 degrees C to +150 degrees C.

Q. Can I get a step resolution smaller than 1.8″?

A. All of our motors are a standard 1.8″ in full-stepping. You can change the size of the step by purchasing drives that either have half-stepping or microstepping capabilities.

Q. How does a step motor work?

A. A step motor has two primary pieces, the rotor and stator. The stator is made out of coils of wire called the windings and the housing. The rotor is a magnet with teeth which rotates on bearings inside the stator. When current is passed through the stator windings, it produces a magnetic force that holds the rotor in a locked position, the amount of torque needed to exceed this force is called the holding torque. As current is switched in the windings, the motor takes “steps” or small movements in one direction. This movement is similar to the second hand on a clock. The amount of rotational movement per step depends on the construction of the motor. If you increase the frequency of the steps you will eventually go from a stepping movement to continuous rotation.

Q. What is the difference between series and parallel connection on an eight lead step motor?

A. On eight lead motors, you have four independent windings with two leads coming out of the motor. Each winding is paired with another. When you connect the pairs to the motor, you are literally connecting them in series or parallel. Depending on how you connect your motor the electrical characteristics change. It is important to know how these characteristics change or else you could damage the motor.

Q. What is stepper motor resonance?

A. Resonance is an unstable condition when running a step motor. Resonance usually occurs between 2-4 rev/sec and can be alleviated in most situations by putting a load on the motor, changing from full stepping to half or microstepping, or increasing your acceleration through the resonance zone.

Q. How does my power supply affect the top speed of my motor?

A. Each motor when turning acts as a generator, pumping voltage back into the drive. This is called the Electromotive Force, or back EMF voltage. The amount of EMF generated increases proportionately with the speed and inductance of the motor. Theoretically, when the back EMF equals the voltage into the drive, the motor stalls. Knowing this information, we can see that if we increase the voltage of the power supply, we are able to reach higher speeds.

Q. I need to either have my stepper drive or motor a far distance from my controller. What distance can I have between the two?

A. The distance from the drive to the motor can be up to 50 feet with the standard cable. If you need further distance you can use a shielded, low inductance cable that is larger gauge (ie. a motor with AWG 24 gauge wire should have an AWG 20 gauge cable). With our step and direction drives, you can have 50 feet between the source of the pulses and our drive, using a shielded cable. If you are communicating via serial RS232 to a computer, most stepper drives can be up to 25 feet from the computer.

Q. How many motors can I run with one drive?

A. Our drives are designed to run one motor. However, you can run more than one motor on a drive, but we suggest series connecting the motor windings to one another (which will limit your top speed). If connecting two motors to one drive, you do so at your own risk.

Q. How do I choose a step motor?

A. In our catalogs are various torque vs. speed curves. When you know the torque required and your top motor speed (rev/sec), look at these curves to determine which motor will work for you. We recommend doubling (100% safety factor) your required torque at a given speed and then selecting a motor/drive/power supply combination that can deliver that torque (i.e. If you need 100 oz-in to the system, get a motor that produces 200 oz-in at that speed).

Q. What is a reasonable inertia ratio between a motor and load?

A. This depends on the acceleration that you expect out of a system. With stepper motors, it is best to target a 1:1 inertial load to motor ratio to expect good acceleration. For servo motors, target for a 5:1 mismatch. Note: gearheads are a good option to reduce the ratio mismatch because the gearhead reduces the reflected inertia by the square of the gear ratio.

Q. Which stepper drive should I choose?

A. The easiest way to choose a motor is to look at our torque vs. speed curves in our catalog and see what type of drive was used with a particular motor. Another method is to find the output power of the motor shaft where: P = T*W/22.5 P is Power in Watts T is the torque in oz-in W is the rotational speed in rev/sec. Take this number and double it. The resulting power will allow you to adequately size the drive for the application. The other thing that you need to consider is how you want to control the motor and how you are powering the drive. The three types of controls with our drives are the internal oscillator, external step and direction, and intelligent drives/controllers. These also come with and without internal power supplies, so depending on your application, choose the drive that is best for you.

Q. Which power supply should I choose for my servo amplifier or stepper driver?

A. The two types of power supplies are regulated and unregulated. We prefer unregulated power supplies since the current doesn’t “fold back” when it gets too high. However, an unregulated power supply’s voltage may spike and blow the drive if you do not size the power supply’s voltage a little lower than the drive’s input voltage. The current on your power supply can be greater than the drive’s, but it should not be less than the rated current of the motor. Otherwise you will sacrifice the performance of your motor.

Q. What does angular velocity mean?

A. It is the RPM the lead screw of a step motor linear actuator must turn at to achieve the desired traverse speed.  RPM= Linear Traverse (inches per minute) divided by Lead (in inches)

Q. Why does my step motor shaft fail to turn?

A. No power to drive – check if AC voltage is present by checking if the green LED indicator on the drive is illuminated. Open motor windings – check that each motor winding phase has the appropriate resistance with no open coils. No incoming pulse – check for proper level and width of pulse at Logic pin No power logic – check to see that Logic Pin (ENABLE/NO POWER) is “High” or open. Low power logic – check to see that Logic Pin (HI/LO POWER) is “High” or open. Fixed load – check to see that driven load is not jammed or too large a load for the chosen motor size.

Q. Why is my step motor motion erratic?

A. Improper lead connections – confirm that the leads of the motor are connected with the proper sequence. Winding continuity – check to see that each phase of the motor has the appropriate resistance with not shorts between windings or to the housing. Incoming pulse integrity – confirm that the pulses being supplied to the driver are the proper level and width and that the rates are not too fast for the motor to maintain synchronism. Resonant instability – confirm that the motor is not operating in a resonance range by adjusting the pulse rate. Current profile adjustment – confirm that the dip switches are set for selected motor. If the problem of rough microstepping persists then the following procedure is recommended. Adjust the pulse rate to achieve a shaft speed of one revolution per second, next adjust the dc-offset to fine tune the drive to the selected motor.

Q. Why does my step motor run very hot?

A. Normal operating mode – it is normal for step motors, when run at their rated current, to be hot to the touch when operating. In general, if the motor case temperature is less that 85 degree C., there is no cause for concern. Current set too high – check to see that the current is set at the appropriate level for the motor being operated.

Q. Why does my step motor fail during acceleration or while running?

A. Improper acceleration rate – check that the increasing rate of pulses feed to the drive is not too fast for the motor to maintain synchronism with the driven load. Improper current setting – step motors require maximum current draw during acceleration. Be sure to match your motor current requirement to that of the driver. Erratic loading – if the driven load dramatically changes while motor is driving, it could overcome the speed/torque capability of system – try to run the motor with the load disconnected. No power logic – be sure that Logic Pin (ENABLE/NO POWER) is “High”

Q. Is it safe to use a DC power supply voltage higher than the voltage rating specified for the motor?

A. a. Normally this not a problem as long as the motor operates within the speed and current limits set by the manufacturer. Since motor speed is proportional to the voltage across the motor leads, select a power supply voltage that could not cause a mechanical over-speed in the event of an amplifier malfunction or a runaway condition. Furthermore, always ensure the motor meets the minimum load inductance requirements of the amplifier and make sure the current limit is set to less than or equal to the rating of the motor.

Q. How do I select the proper power supply rating for my application?

A. a. It is recommended to select a power supply voltage that is about 10 to 50% higher than the maximum required voltage for the application. This percentage is to account for the variances in Kt, Ke, and losses in the system external to the amplifier. b. The current rating of the amplifier should be high enough to deliver enough power for the application. Remember that the equivalent output voltage of the amplifier is not the same as the supply voltage, therefore the amplifier output current will not be the same as the current from the power supply. To determine thte appropriate current rating for the power supply, calculate total power required by the application and add 5%. Divide this power requirement by the supply voltage (I=P/V) to find the required current.

Q. Why do step motors run hot?

A. Two reasons here, first full current flows through the motor windings at standstill, secondly PWM drive designs lend to make the motor run hotter. Motor construction, such as lamination material and riveted rotors, will also affect heating.

Q. What is the safe operating temperature of a common stepper motor?

A. Most stepper motors have class B insulation which is rated at 130 degrees C. Motor case temperatures of 90 degrees C will not cause thermal breakdowns. Motors should be mounted where operators cannot come into contact with the motor case.

Q. What can be done to reduce motor heating?

A. Many drives feature a “reduce current at standstill” command or jumper. This reduces current when the motor is at rest without position loss.

Q. Will motor accuracy increase proportionately with higher step resolutions?

A. No, since the basic absolute accuracy and hysteresis of the motor remains unchanged.

Q. Can I use a small motor on a large load if the torque requirement is low?

A. Yes, however, if the load inertia is more than ten times the rotor inertia, cogging and extended ringing at the end of the move will be experienced.

Q. How can end of move “ringing” be reduced?

A. Friction in the system will help dampen this oscillation. Acceleration/deceleration rates could be increased. If start/stop velocities are used, lowering, or eliminating them will help.

Q. Why does the step motor stall during no load testing?

A. The motor needs inertia roughly equal to its own inertia to accelerate properly. Any resonance’s developed in the motor are at their worst in a no load condition.

Q. Why is motor sizing important, why not just go with a larger motor?

A. If the motor’s rotor inertia is the majority of the load, any resonances may become more pronounced. Also, productivity would suffer as excessive time would be required to accelerate the larger rotor inertia. Smaller may be better.

Q. What are the options for eliminating resonance?

A. This would most likely happen with full step systems. Adding inertia would lower the resonant frequency. Friction would tend to dampen the modulation. Start/stop velocities higher than the resonant point could be used. Changing to half step operation would greatly help. Ministepping and microstepping also greatly minimize any resonant vibrations.

Q. Why does the step motor jump at times when it is turned off?

A. This is due to the rotor having 50 teeth and therefore 50 natural detent positions. Movement can then be +/- 3.6 degrees, either direction.

Q. Do the rotor and stator teeth actually mesh in a step motor?

A. No. While some designs use this type of harmonic drive, in this case, an air gap is very carefully maintained between the rotor and the stator.

Q. Does the motor itself change if a microstepping drive is used?

A. The motor is still the standard 1.8 degree stepper. Microstepping is accomplished by proportioning currents in the drive. Higher resolutions result.

Q. A move is made in one direction, and then the step motor is commanded to move the same distance but in the opposite direction. The move ends up short, why?

A. Two factors could be influencing the results. First, the step motor does have magnetic hysteresis which is seen on direction changes. This is in the area of 0.03 degrees. Any mechanical backlash in the system to which the motor is coupled could also cause loss of motion.

Q. Why are most step motors constructed as eight lead motors?

A. This allows greater flexibility. This type of step motor can be run as a six leaded motor with unipolar drives or as an eight leaded motor with bipolar drives connected in either series or parallel.

Q. What advantage do series or parallel connection windings give?

A. With the windings connected in series, low speed torque’s are maximized, but this also produces the most inductance so performance at higher speeds is lower than if the windings were connected in parallel.

Q. Can a flat be machined on the motor shaft?

A. Yes, but the motor must be disassembled so the flat can be machined on the shaft. Care must be taken to not damage the bearings, the stator windings, and the rotor during disassembly.

Q. How long can the motor leads be?

A. For bipolar drives, 100 feet. Unipolar designs, 50 feet. Shielded, twisted pair cables are required.

Q. Can specialty motors; explosion proof, radiation proof, high temperature, low temperature, vacuum rated, or waterproof be provided?

A. Yes. Specialty servo or stepper motors are available for a variety of harsh environments. Contact us for more details.

For more information, please contact:

EDITORIAL CONTACT:

Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

Tags:  Step Motor, DC Step Motor, Stepper Motor, BLDC Motor, Automation, Motion Control, FAQ

Stepper Drive Questions and Answers – Avoiding Common Mistakes

Question:  What is the most common mistakes that engineers make when specifying and working with stepper drives?

Answer:  Believing that a motor will achieve the data sheet’s rated speed-and torque when it is matched to “any” driver.  Just like a servo, the stepper motor’s stall torque, rated torque, and rated speed are all dependent as much on the drive and motor being matched as they depend on the available voltage and current.  A performance curve (speed-torque-curve) with a matched drive is the most reliable reference.   Also, a motor’s stall torque is not an indication of the torque a motor can generate while moving — especially during acceleration and deceleration where higher torque is required…

Click on the link below to download this complete White paper.

http://www.electromate.com/db_support/attachments/KOL_StepperDrive_Paper_Finalvrsn%20v2.pdf

Information on Electromate’s family of stepper motors and drives can be viewed at the link below-

http://www.electromate.com/products/?keyword=stepper&product=&partner=&x=0&y=0

For more information, please contact:

EDITORIAL CONTACT:

Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

Tags:  Step motor, step driver, stepper motor, stepper driver, Kollmorgen, Electromate, Automation, Motion Control

New NEMA 17 and NEMA 23 Integrated Motor/Drivers from Nippon Pulse

Nippon Pulse America’s PRO Series NEMA 17 and NEMA 23 integrated motor/drivers are ideal for machine designs where an incorporated motor/driver helps conserve space.  These hybrid stepper motors with attached drive electronics yields a compact, RoHS compliant package.

Nippon Pulse PRO Series Integrated Motors

Nippon Pulse PRO Series Integrated Motors

PRO Series hybrid stepper motors are precision designed for medical technologies and semiconductor manufacturing applications.  They deliver accurate open loop control for high performance positioning applications.  Two models, PRO 42AP with 1/500 microstepping, and PRO 42BP with 1/8 microstepping are available.

The PRO series integrated driver solution can lower installed cost.  This motor/driver package provides high torque density and simplified operation through attached drive electronics.  This can remove the need to run motor power management cabling through the machine, and may reduce the potential for electrical noise.

These motors are available in case lengths of 40, 48, and 60 mm.  Depending on the case length, the PRO Series Size 17 motor can produce maximum holding torques (bipolar) ranging from 300 to 440 mNm.

The PRO Series is available in two models: AP 100,000 steps and BP 16,000 steps resolution.  Precision-honed stators and ground rotors for tight air gap and maximum performance; and simple, rugged, ball bearing construction provide high reliability and long service life.  An attached encoder is optional on both AP & BP models.  Selectable PFD (Percent of Fast Decay) is available with the advanced AP version.

Designers can use these integrated stepper motors to build laboratory analytical devices with motion control needs that may include stirring, fluidics, and sample selection.  Other applications for the PRO Series Integrated Motors include X-Y tables, semiconductor handling, telecommunications equipment, valve control, small machinery, and other automated devices that require precise remote controlled rotary movements in a compact package size.

More information on the PRO Series Integrated Motors from Nippon Pulse America can be viewed at-

http://www.electromate.com/products/series.php?&series_id=102182

For more information, please contact:

EDITORIAL CONTACT:

Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com


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