Archive Page 2

Clutches- What you need to know


A clutch is a mechanical device that engages and disengages a power transmission, especially from a driving shaft to a driven shaft.  Clutches are used whenever the transmission of power or motion must be controlled over a time element (ie. electric screwdrivers limit how much torque is transmitted through use of a clutch).

In the simplest application, Power-on Clutches connect and disconnect two rotating shafts (drive shafts or line shafts).  In these applications, one shaft is typically attached to an engine or other power unit (the driving member) while the other shaft (the driven member) provides output power for work.  Although the typical motions involved are rotary, linear clutches are also possible.

Generating the Clutch Torque

Power-on Clutches and Brakes are designed to start and stop inertial loads when the voltage is turned on. When DC voltage is applied to the coil, the magnetic force caused by the magnetic flux pulls the armature across the air gap against the force of the zero-backlash spring attached to the armature.  The mating of the armature and rotor face produce torque.

When DC voltage is interrupted, the magnetic field collapses, and the zero-backlash spring retracts the armature from the rotor face.  Thus there is no residual torque produced.

Common Types of Clutches

Electromagnetic clutches are typically engaged by an electromagnet that is an integral part of the clutch assembly.

Magnetic particle clutches contain magnetically influenced particles in a chamber between the driving and driven members and application of direct current makes the particles clump together and adhere to the operating surfaces.  Engagement and slippage are notably smooth.

Wrap-spring clutches have a helical spring typically wound with square-cross-section wire.  The spring is fastened at one end to the driven member; its other end is unattached.  The spring fits closely around a cylindrical driving member.  If the driving member rotates in the direction that would unwind the spring, the spring expands minutely and slips although with some drag.  Because of this, spring clutches must typically be lubricated with light oil.  Rotating the driving member the opposite way makes the spring wrap itself tightly around the driving surface and the clutch locks up very quickly.

Clutches/Power-On Brake packages are used to couple two parallel or in-line shafts. The clutch armature hub can accommodate a pulley, gear, sprocket, etc., to transmit torque to the second shaft.  The brake is used to stop or hold the load.

How to Size & Select Electromagnetic Clutches

CLICK HERE to download a White Paper on Selecting a Power-On Clutch.

Typical Applications of Clutches

  • Copiers/Printers
  • Packaging Machinery
  • Microfilm Readers
  • Medical Equipment
  • Conveyors
  • Postal Sorters/Readers
  • Document Feeders
  • Textile Equipment
  • Mobile Power Equipment

CLICK HERE to view Electromate’s Clutch product family.

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:  Clutch, Electromagnetic clutch, wrap-spring clutch, clutch/power-on brake, Electromate, Inertia Dynamics, magnetic particle clutch, Power-on Clutch

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

LEAD SCREW LINEAR ACTUATORS: When to Apply External, Non-Captive and Captive Step Motor Actuators

Haydon Kerk Product Family

Haydon Kerk Product Family

A common way to generate precise linear motion is to use an electric motor (rotary motion) and pair it with a lead screw to generate a linear actuation system.  Depending upon what this linear actuator interfaces with it can be constructed in a number of different ways.  Here we will discuss several different ways to combine a lead screw and nut with a stepper motor to create a linear actuator system…

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

LEAD SCREW LINEAR ACTUATORS: When to Apply External, Non-Captive and Captive Step Motor Actuators

Electromate’s complete family of Step Motor Linear Actuators can be viewed at the link below-

http://www.electromate.com/step-motor-linear-actuators.html

 

Tags:  Lead Screw Linear Actuator, Step Motor Actuator, Captive Step Motor Actuator, Non-Captive Step Motor Actuator, External Step Motor Actuator, Electromate

Introducing the Linear Encoder Family of MicroE Systems

MicroE Sytems Linear Encoders

MicroE Sytems Linear Encoders

MicroE Systems was founded in 1994 to advance encoder technology.  Seizing the trend toward smaller motion systems, their patented optical designs have led to over 30 different encoder models today.  These innovations make encoders that achieve higher accuracy and speed while also being smaller, easier to install, and use less power.  That’s why so many OEMs are putting MicroE Systems encoders in their designs.

MicroE Systems’ encoders are renowned for their small size, ease of setup and features.  But more customers are also discovering their world class performance—lower cyclical error for better velocity control, accuracy to ±1µm, and resolution that’s stable up to 1.2nm.

All of this performance comes from a 20µm-pitch encoder system that’s a fraction of the cost of 4µm and 2µm pitch encoders—now that’s value.

Features commmon to all MicroE Systems Encoders:

  • Compact and tiny sensors
  • Wide setup tolerances
  • User-programmable resolution
  • Robust tolerance to scale contamination
  • Low power consumption
  • Software for encoder setup and data plots

MicroE Systems’ family of Linear Encoders includes:

Performance and Value Linear Encoders

Tape Scale Linear Encoders

High-Performance Linear Encoders

Compact Linear Encoders

High Vacuum Linear Encoders

Information on the full family of MicroE Systems linear encoders can be found at the link below-

http://www.electromate.com/linear-encoders.html

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:  MicroE Systems, Celera Motion, Linear Encoder, Electromate

 

Do you know the difference between these 10 types of servomotors?

Servomotors are generally used as a high performance alternative to the stepper motor. Stepper motors have some inherent ability to control position, as they have built-in output steps. This often allows them to be used as an open-loop position control, without any feedback encoder, as their drive signal specifies the number of steps of movement to rotate. This lack of feedback though limits their performance, as the stepper motor can only drive a load that is well within its capacity, otherwise missed steps under load may lead to positioning errors. The encoder and controller of a servomotor are an additional cost, but they optimize the performance of the overall system (for all of speed, power and accuracy) relative to the capacity of the basic motor. With larger systems, where a powerful motor represents an increasing proportion of the system cost, servomotors have the advantage….

Click on the link below to read this complete article.

http://www.electromate.com/servo-motors.html

 

Tags:  servo motor, brushless motor, brush motor, BLDC motor, slotted motor, slotless motor, linear motor, voicecoil motor, pancake motor, moving coil rotor motor, iron core motor, frameless motor, direct drive motor

 

Measuring Wheels turn Rotary Encoders into Linear Position Sensors

Posital Measuring Wheel Encoder

Posital Measuring Wheel Encoder

POSITAL has introduced a series of measuring wheel accessories for its IXARC family of rotary encoders. When one of these wheels is mounted on the shaft of an encoder, the result is an accurate and reliable instrument for measuring linear motion and position. “Rotary encoders do a great job of measuring rotary motion in shafts and other machine components,” comments Jarrod Orszulak, Product Manager at POSITAL-FRABA Inc. “However, for many motion control systems, accurate linear positioning is the main objective. With the new measuring wheels, we have a very convenient way of making linear displacement measurements while taking advantage of the proven performance of our extensive line of rotary encoders. This is a great solution for equipment positioning tasks or for cut-to-length applications.”

The new measuring wheels are available in circumferences of 200 mm and 500 mm. When fitted to multi-turn IXARC absolute encoders, this would translate into a linear measurement range of up to 500 kilometers! Three rim treatments are available – knurled aluminum, smooth polyurethane and textured (knobby) polyurethane – to ensure good traction between the wheel and a variety of surfaces.

Orszulak continues: “We are very excited about the combination of measuring wheels and our programmable incremental encoders.  With this arrangement, a user could define exactly how many pulses the instrument would produce for a defined unit of linear motion”. IXARC programmable encoders can be easily calibrated at the job site using POSITAL’s convenient UBIFAST programming tool.

More information on POSITAL’s measuring wheels can be found at-

http://www.electromate.com/posital-fraba.html

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:  Posital, Posital Fraba, Wheel Encoder, Measuring Wheel, Electromate, IXARC, rotary encoder

 

Introducing Akribis Systems’ Voice Coil Motors & Voice Coil Position Actuators

A “voice coil” is a generalized term that refers to any galvanometer-like mechanism that uses a solenoid to move an object back-and-forth within a magnetic field.

Voice coil actuators, or non-commutated DC linear actuators, consist of a permanent magnetic field assembly (permanent magnets and ferrous steel) and a coil assembly.  The current flowing through the coil assembly interacts with the permanent magnetic field and generates a force vector perpendicular to the direction of the current.  The force vector can be reversed by changing the polarity of current flowing through the coil.

Voice coil actuators are typically used in focusing applications, oscillatory systems, mirror tilting, and miniature position control.

Electromate offers a full family of Voice Coil Motors & Voice Coil Modules from Akribis Systems.  Features include:

  • Direct drive, zero cogging, and zero backlash
  • Low coil mass with very fast response and bandwidth
  • No contact between coil and core movement (no wear and tear)
  • Cylindrical or rectangular shape
  • A variety of Voice Coil Motors and Voice Coil Modules (Position Actuators)
  • Smooth motion at low speeds with limitless resolution (depends on feedback device)

CLICK HERE to view the Akribis Voice Coil Motor & Voice Coil Module Family.

Akribis Systems designs and manufactures servo motors, stages and precision systems that are used in equipment for manufacturing, inspection and testing. Products include: ironless linear motors and stages, iron core linear motors and stages, voice coil motors and modules and direct drive rotary motors, and complex precision systems.

Akribis Systems supports a wide range of industries including semiconductor, flat panel, data storage, photonics, biomedical, life science and electronics manufacturing.

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:  Akribis, Akribis Systems, Voice Coil Motor, Voice Coil Module, Voice Coil Actuator, Electromate


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