Electromechanical Blog

This is the final of a three-part series that spoke to the various feedback devices that are provided as options on Parker Servo Motors. Part 1 & Part 2 provided the basic theory of operation for the devices and provided some guidance on why you might choose one versus the other, along with some helpful formulas for calculating required resolution. The following is a quick summary and recommendations on selecting the best feedback device for your motion control application.

You might notice a trend that takes the customer from the “paper napkin sketch” to the “electronic or digital napkin sketch.” With the increasing use of 3D CAD systems, customers can use electronic tools to create their designs. The user libraries can be downloaded from the web and all the parts and components become available for use in your CAD system. Some companies offer a plug-in to a specific 3D CAD system. This means that their software works with that specific 3D CAD system, which may or may not be the system that you’re using. Other companies offer a standalone tool that can export files into various 3D CAD formats.

Here are a few ways to access these tools

• License or seat for your computer (paid)
• Free download
• Web-based (free or paid)

With so many projects and the time constraints that go along with them, it is important for users to work efficiently. Using an electronic tool to “sketch” your design will allow you to import that assembly into your current project. This is very valuable if it is part of a larger machine design. Also, being able to interact with a trusted partner to quickly receive a quote helps with the process of understanding project costs along the way.

Are you ready to take your concept to completion? Start with the Parker T-Slot Aluminum Design Architect (TADA). This is a free tool that you can use to design your tables, carts, workstations, enclosures and more. We also have a network of Design Centers located throughout North America that are ready to help you with your design needs using T-slot aluminum framing.

Parker is making t-slot aluminum framing design easier than ever. For mechanical design engineers, lean manufacturing leaders and do-it-yourselfers, the Parker T-Slot Aluminum Design Architect (TADA) software allows you to take more creative control over your assembly designs. Download your free, fully functional copy today.

Article contributed by Mario Mitchell, product manager for T-slot Aluminum Framing, Electromechanical & Drives Division North America, Parker Hannifin Corporation. 

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Stretch films are essential in the packaging industry as they provide a versatile and high-quality solution for packing products in a safe and economical way. Film is produced by a flat die extrusion process where AC motors and AC variable speed drives play a significant role in ensuring a high-quality output.

The process starts with the extruder that is essentially a pump that melts and transports fluids of high viscosity. The polymer enters into the extruder via a gravimetric feed, and through the combined actions of heat and mechanical stress, the material is melted, mixed and pushed through an extrusion head to give the desired shape. After exiting the extrusion head, the material enters a cooling unit, here water cooled ‘chill rolls’ reduce the temperature of the film before it is finally wound onto rolls.

The extruder consists of a hollow cylinder in which rotates a single or double screw driven by an electric motor; this is usually coupled to the plasticising screw by a gearbox. The motor provides the torque required and rotates at a speed necessary to obtain the expected melt flow rate. Any failure in the precise control of the screw speed can cause changes in film thickness in the machine direction.

For the past 20 years, AC motors have typically taken over from DC motors in the control of the extruder screw in cast film line applications. They have been able to deliver many advantages in terms of convenience, reliability, low maintenance and a reduction in the overall dimensions of the system solution. AC motors are controlled by AC variable speed drives that guarantee stable rotation - even at very low speeds (via a closed loop circuit through incremental encoders), provide short circuit protection (low or high voltage), and incorporate EMC filters to eliminate electrical noise and interference.

In recent years, along with AC motors and drives, torque motors have also been utilised in screw extrusion control. These offer a complete direct drive solution that does not require the assembly of different elements such as a gearbox, belts and pulleys. Torque motors guarantee uniformity in the motion, linearity and constancy in the extrusion of the plastic material.

As previously mentioned, when the material leaves the extrusion head, it is melted on chilling rolls that form the cooling section of the cast film production line. The cooling unit is comprised of a primary quenching roll, that cools the film on one side, and a secondary roll, that cools the film on the opposite side. It also includes a motorised roll positioning system for correct vertical and cross machine direction alignment of the rolls, and in many cases a vacuum box and/or air knife.

The rolls must be perfectly aligned with the web to guarantee uniform tension and to minimise thickness variations across the width of the film.  In addition, the angular velocity of the rolls must be well controlled to prevent film thickness fluctuations in the machine direction.

Within the cooling and winding sections we find the accumulator, this is used to allow splicing of the web being fed from an empty winder to a full winder at zero speed without stopping the line.

At the end of the process, a further winder brings the extruder material onto rolls. The winding process has to preserve the film’s properties and dimensions when the rolls are unwound in other downstream processes.

There are several different types of winders, although the typical one used one in cast film applications is a ‘turret’ or ‘centre’ winder where the web tension decreases as the roll diameter increases.

All the movements performed in the cooling, accumulator and winder sections are driven by AC motors and drives that govern the web speed and the correct web tensioning.

AC Drives and Motors

AC Drives with high-end control are very important for guaranteeing high-quality film throughout the process. Easy-to-configure software for the closed loop control and optimum efficiency for many different types of material is a vital element of a cast film line system and process.

Parker's AC30 series with power ratings ranging from 0.75 to 450 kW coupled with the company’s Quicktool software with full IEC61131PLC functionality or Parker DSE Lite software, provides all the features needed to achieve optimum synchronisation between all line sections. It allows customers to create, parameterise and configure user-defined applications using dedicated function blocks such as the winder, PID and diameter calculator. The AC30 series also provides access to a large library of application macros and worked examples.

Connectivity via EtherCAT, Profinet, Ethernet IP and Modbus TCP IP through a dual Ethernet port enables communication between individual drives in a simple and flexible way and supports intelligent data analytics and connection to external servers. The line setpoint can be sent through a very fast channel supported by 1588 time synchronised peer-to-peer communication, and each part of the machine has its own regulation, either within the drives, or through communication protocol by the PLC.

An animation shows how high a performance drive solution supports the optimal control of a cast film line.

Article contributed by Jean-Philippe Olry, application engineer industrial market, Electromechanical & Drives Division Europe of Parker Hannifin Corporation.

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A Simple Guide to Benefits of Electromechanical Technology

Using a variable frequency drive (VFD) can be beneficial in many constant speed applications driven by electric motors, such as those that require controlled starting and have been historically served by a reduced voltage soft-starter (RVSS). While an RVSS and a VFD can both provide a controlled start, let’s examine the benefits of each technology and when it makes sense to use one over the other.

To learn more details about when to use a VFD in place of an RVSS, download the full white paper.

The differences between RVSS and VFDs and when to select one or the other for an application is determined by the following factors (when using a NEMA design B three phase induction motor):

• Across-the-line starting results in inrush current between 600% to 800% (locked rotor current) and produces approximately 200% of rated torque (locked rotor torque).
• The sudden acceleration of the load from the 200% torque surge generated when across-the-line starting.
• Zero driving torque when the starter is de-energized resulting shock loading to the piping and connection components (water hammer effect).

An RVSS can be used to limit inrush current and reduce mechanical stresses on the motor and device it is powering during the starting cycle. The RVSS ramps the starting voltage from 40% (typical) to 100% over a set time (2 - 15 seconds typical). Starting torque is significantly reduced, rising to full torque at rated voltage.

By using an RVSS, locked rotor torque will be approximately:
Rated Torque x 2 x (% applied voltage)2

At a 40% start voltage, locked rotor torque will be:
Locked Rotor Torque = Rated Torque x 2 x (0.40)2 = 0.32  (32% of rated torque)

• Reducing the inrush current can lessen brownouts and help avoid peak demand surcharges. The reduced starting torque decreases stress on the motor windings and minimizes motor heating caused during across-the-line starting.
• An RVSS can, in certain cases, allow more frequent starts per hour than across the line starting.
• An RVSS can also help mitigate the water hammer effect when stopping a centrifugal pump.

• An RVSS produces substantially reduced starting torque.
• An RVSS does not provide controlled variable speed operation nor the ability to change rotation without a reversing contactor.
• Due to the phase angle controlled variable voltage waveform, an RVSS creates significant harmonic distortion and reduced power factor during the start cycle.

Because both the voltage and frequency are varied with a VFD, the motor will be at 100% flux at any speed resulting in the ability to produce 100% torque at 100% current at any speed below base speed. Therefore, a VFD can be used as a full torque soft starter in place of an RVSS. When used in this capacity, a VFD is capable of starting loads that require up to 200% torque such as mixers and production machinery with no inrush current.

• Varying speed optimizes the process.
• A VFD can reverse rotation without an expensive reversing contactor set and wiring.
• Smooth, controlled acceleration and deceleration minimizes mechanical stresses and water hammer effect if used on a pump.
• No bypass contactor required.
• Because the VFD is 100% rated and the current does not exceed 100%, the number of starts per hour is unlimited.
• Harmonic distortion is significantly less that that created during the start cycle of a phase angle controlled RVSS.

Parker has recently introduced the AC10 series of general purpose VFDs, available at 230V to 20HP and 460V to 250HP and offer:

• Easy configuration via an onboard keypad or with Parker’s DSELite software.
• Built-in RS422/485 communications.
• High starting torque, unlimited starts per hour and rotation reversal.

To learn more about Parker's VFD products, please visit our website.

Download the full white paper to learn more about the advantages of variable speed drives and when to use them
in place of RVSS.

Article contributed by Bill Riley, business development manager for the Drives Business Unit, Electromechanical & Drives Division North America, Parker Hannifin Corporation. 

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For a long time, the use of hydraulic power in industrial processes has been associated with its traditional benefits: high power density, precise control, and long-term performance. Yet these advantages typically come hand-in-hand with equal numbers of potential drawbacks: excess noise, heat generation, and inefficient energy allocation. As we move forward, technologically advanced industrial equipment now requires hydraulic systems that can provide quieter, more economical and more efficient solutions.

Where wasted energy and resulting carbon emissions might have previously been seen as inconsequential, a switch to a tightly-modulated hydraulic system fitted for specific tasks is essential in today’s globally competitive and eco-conscious economy. With various industrial machinery (including die casting machines, presses and plastic injection moulding machinery) placing different demands on hydraulic control, you may wonder: how can highly complex hydraulics systems be adapted for individual requirements?

Taking one application example into consideration – injection moulding machinery (used in rubber, thermoplastic and other polymer industries); Parker has developed an immersed servo motor pump system with the aim of enhancing hydraulic reliability and reducing energy consumption. Hydraulics have long been utilised in this industrial process; with a hydraulic power unit (HPU) as the source and with very large capacity pumps and motors to ensure steady performance. However, Parker’s solution brings in three separate elements (a pump, a servo motor and a drive for control) to match flow rate to the particular requirement, primarily through the rotational speed of the motor.

From opening and closing moulds to plasticising and injecting, there are many auxiliary movements – often occurring in parallel – that take place within plastics machinery. They must be supplied centrally with the required flow and pressure over the briefest of cycle times. Controlled by the speed and torque of servo motor as part of Parker’s solution, careful flow and pressure regulation allows for greater energy efficiency. With the high maximum speed of the small vane pump, a very high volume flow can be achieved with the smallest size. Therefore, component size can be optimised to suit their need and investment costs reduced.

Alongside hydraulic systems available for injection moulding machinery, Parker offers a full-system solution, the Drive Controlled Pump (DCP), which combines a versatile range of AC drive controllers, motors and pumps into tailored packages for the most diverse applications. With the incorporation of an alternating current drive controller, the speed range can be set in advance to a predefined cycle. Whether for a long or short duty cycle, the precise amount of hydraulic power required can be calculated for any particular point in time. When selecting between vane pumps or axial piston pumps, factors of output, required minimum and maximum speeds can be assessed and taken into consideration.

Parker’s DriveCreator dimensioning software tool enables the creation of an energy-efficient, speed-controlled, electrohydraulic DCP solution, while its start-up tool simplifies the task of putting the DCP into operation once selected. To discover more about recommended combinations of individual components, please click here.

This article was contributed by Vincent Sinot, key account manager, Parker Sales Company France.

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Although the basic recipe for the solid soap bar has not varied much for decades, the process of making this basic commodity has changed significantly since the advent of industrialisation. Modern factories now produce thousands of pieces of soap per day.

Hirtler Seifen GmbH, from Heitersheim, Germany, is one such soap manufacturer, but unlike many of its peers, it has a history spanning over 125 years. From its traditional origins, the company has grown to become one of the largest manufacturers of soaps and cleansing products in Europe, delivering its products to customers all over the world.

However, the company’s plant was in need of an upgrade to optimise its production line for efficiency, production output and recipe-change flexibility. Hirtler Seifen’s 20-year-old digital servo controllers had reached the end of their useful life, and the rest of the system’s associated components could not be upgraded without undertaking a complete system overhaul.

Automation solution providers Mattke AG from nearby Freiburg were tasked with bringing Hirtler Seifen’s production line completely up to date with the newest precision movement technology. They realised that this was more than just a simple controller exchange task, because Hirtler Seifen’s primary goal was to increase its production rates from 5,000-6,000 bars of soap per day up to 15,000. They also required greater flexibility to accommodate production line changes.

As the plant was already running 24 hours a day, seven days a week, reducing maintenance-related downtime through better equipment reliability and positioning accuracy was identified as one of the ways in which production could be stepped up.

The decision was made to completely replace the linear axles, motors and servo controllers, from the pre- and post-production handling portals to the cooling system for the soap-free cleansing bars. Mattke selected Parker's LBB080 toothed belt linear actuators, SMH-Series low-inertia brushless servo motors and COMPAX3S single-axis servo drives for the job.

Hirtler Seifen set Mattke a challenging delivery date: the factory was to be closed for just four weeks, during which time the entire refit had to be completed. Throughout this very tight overhaul period, Parker provided essential custom manufacturing support to Mattke.

After the CAD drawings were completed and system requirements were finalised, Parker worked quickly to complete the mechanical axles for the handling portals, complete with electric thrust cylinder, linear actuators, servo motors and drives, in just three weeks – half the time usually required for such a task. During this time, Mattke’s engineers were hard at work setting up the system software. When the mechanical equipment arrived on-site, the team had just one week to install and set up in time for production to begin.

The project was delivered on time thanks to the close collaboration between Mattke and Parker.

“Our partner, Parker, who manufactured the mechanical axles, put in a great deal of effort and provided a high degree of technical expertise.”

Simon Hübner, technical director, Mattke AG

In addition to the significant increase in volume provided by the overhaul, the new system now offers Hirtler Seifen increased flexibility.

Each of the five products that are currently manufactured by Hirtler Seifen can be manufactured at the same time, but still managed separately. And if the soap manufacturer wishes to add more products to the production run, this will be an easy task.

This article was contributed to by Michael Boerner, key account manager, Automation, Parker Hannifin Germany

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The renewal of the entire ventilation system in the underground car park serving the largest European business district, was not limited to the simple replacement of filters and some mechanical components. This operation involved a vast project requiring advanced technical expertise, particularly in terms of defining and selecting drive solutions and supporting their integration, installation and commissioning.

The objective of the drive systems for the variation of ventilation speed was two-fold. Firstly, it was a question of ensuring the effective evacuation of exhaust gases. Then, secondly, achieving much faster removal of smoke in the event of a fire. The previously installed system had become obsolete because it was only equipped with two-speed motors without drives.

Parker worked with EDF and Inov Industrie on the project. The company was selected for its technical abilities with respect to drive systems, but perhaps more importantly, for its "know how" in the control of energy consumption/optimisation of energy efficiency. The project presented multiple challenges that had to be overcome. First, the project concerned the most extensive car park in Europe incorporating 22,000 spaces, spread over sixteen different sites. Then, due to the underground location of the car parks, below the towers of La Defense at a complex, major road junction, there were numerous access constraints. To this was added the problem of dimensions: the systems selected had to fit in existing cabinets and be adapted to the protocol already in place.

All of the disassembled components being replaced had to be removed and recycled. Finally, and perhaps most importantly, the fire safety system needed to allow the forced operation of the drives at maximum speed in order to reliably evacuate fumes in the shortest possible time. For safety, the new systems also needed to be equipped with an automatic restart and be directly connected to the emergency fire services.

The nature of the project meant that work had to be completed quickly and efficiently under intense time pressure. The scale of the project meant that a total of 60 drives with power ratings from 5.5kW to 180kW had to be commissioned in a very short space of time. Inov Industrie, with its 20-year working relationship with Parker, turned to the motion and control specialist, opting to specify units from the company’s AC10 compact drive range.

The suitability of the AC10 range for this significant and challenging project was enhanced due to some new features such as fire mode input/output and its wide range of power ratings - all in a compact package. The AC10 range is characterised by its simplicity of installation, setup, and commissioning, thanks in particular to a fast parameterization. With its enhanced functionality, the AC10 drive is able to control asynchronous motors incorporating both simple and complex types of application such as pressure and flow control. The ‘small sequential’ function (sequencing on and off) avoids the need for an additional PLC. It is also possible to obtain information relating to system power consumption and other parameters such as the occurrence of dirty filters.

Article contributed by Francis Scharwatt, sales engineer, Parker Hannifin France

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Meeting Demand for Efficient Automotive Vehicle Testing & Dynamometers

Maintaining a safe and productive work environment should be top priority in any facility. More and more companies are putting programs in place to improve the working environment and thereby increase the performance of workers.

Audible noise is one of the factors most commonly present on the manufacturing floor, since the operation of any equipment or machinery involves the generation of noise at some level. Usually, the lower the technology of the equipment, the greater the intensity of the noise emitted, reaching in some cases to exceed the tolerable or legally allowed levels.

In addition to the risk of hearing loss, excessive noise has been known to cause physiological effects such as fatigue, tinnitus, lack of concentration and stress, even at levels well below 85 decibels (dB). Keeping people working in environments with excessive noise is a safe bet for reduced productivity and lost time.

Excessive noise exposure can be mitigated by addressing several elements. The actions for noise control can be classified according to the element on which they are carried out:

• Noise generation source (machine or equipment)
• Means of propagation
• Receiver (worker)

Directly reducing the noise generated by the source is the ideal option because it eliminates the need to add elements external to the process and results in a more efficient operation, but can potentially require more initial investment. Among the actions of this type we find:

• Update to more modern technologies
• Major maintenance of the machinery

When it is not possible to act on the noise source, or the reduction reached is not enough, it is possible to alter the propagation medium to reduce the sound effect. These actions have the advantage of being able to be carried out without modifications to the production process, representing a fairly low implementation risk. Among these actions we have:

• Cabinets or enclosures for the machine
• Anti-vibration mounts to avoid resonances

The noise control actions in the receiver must be the last ones due to the inconvenience that it generates for the worker and the consequential reduction of the effectiveness of oral communication. These actions are typically:

• Ear protector like plugs and shells
• Enclosure booths for workers

• Dynamic metrology – applications where measurement data is collected while either the measurement sensor or the unit under measurement are in motion
• Static metrology – applications where measurement data is collected while both the measurement sensor and the unit under measurement are at a stable location
• Focusing – a special type of static metrology where an axis, typically vertical, is used to focus on a sample for measurement

When it comes to gearbox test rigs deployed in the automotive and aerospace industries, one thing is certain - there is no margin for failure. A test rig or system that is unreliable or produces erroneous results can have serious consequences to development programmes where designers and research and development engineers are under intense pressure to deliver next-generation solutions to a demanding customer base.

Gearbox test rigs come in many different configurations, depending on the type of transmission being tested. However, most share a common requirement, namely the need for electromechanical components such as high-speed servomotors, inverters and linear motors.

A case in point can be seen at BIA, a French-based industry leader in the design, development and manufacture of test equipment and systems for customers in the aerospace, industrial and automotive sectors. The company has been collaborating with specialists at Parker for a number of years, with the outcome that BIA is now able to combine specific elements and components of its test rigs into completely bespoke, integrated systems that offer higher reliability and performance.

“We very much benefit from Parker’s wide product offering that helps us to efficiently source high quality and reliability components and systems, which finally contribute to BIA’s global success. We appreciate the very constructive spirit with which the dialogue with Parker is conducted." 

Olivier Carlier. project leader at BIA

Parker works closely with customers such as BIA to help define the components required for each individual simulation and test system. Here, the company’s extensive portfolio assists in sourcing high quality, reliable products and systems. Products such as Parker’s high-speed servomotors, for example, are adopted widely in gearbox test rigs for the efficiency of their cooling systems, as are Parker linear motors, chiefly as a result of their positioning accuracy.

Beginning with Parker’s brushless, permanent-magnet, high-speed MGV servomotors, these offer the capability to simulate a combustion engine in conjunction with a vehicle’s manual gearbox. Of particular note, MGV motors benefit from water cooling, which in turn permits their dimensions and operating noise to be minimised. Furthermore, the low inertia of the MGV allows for highly dynamic acceleration and deceleration, while in order to achieve maximum precision, motor speed and torque are controlled in a closed loop, permitting the servomotor to be used for simulations in both urban traffic and race conditions.

Parker MS asynchronous motor are also popular for gearbox testing applications. The reason stems from the fact that the MS can deliver 10,000 rpm at 500 kW, which is ideal for gearbox duration testing – a task which requires a constant, medium speed without acceleration.

On the subject of transmission endurance tests, Parker ETT linear motors are often deployed (including at BIA) to actuate the gear lever and engage gears. Here, the rectangular rod configuration connected to ETT cylinders simulates movement through the standard H-slots of the gear lever. ETT linear motors have a high positioning accuracy of 0.5 mm, along with repeatability of 0.05 mm. 

Also worthy of mention, Parker AC890 inverters have been developed to achieve optimum performance levels with both asynchronous motors (MS) and synchronous servomotors (MGV), and are able to operate in both motor and generator modes. This functionality can be exploited during gearbox tests: one motor can be connected to the gearbox input, just like a diesel engine, while two other motors (operating in generator mode) can be linked with the output of the gearboxes to simulate rotating wheels. This power generation gives full grid energy recuperation and can enable significant energy savings too.

Article contributed by Michel Finck, market development manager, Electromechanical & Drives Division Europe.

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