Don’t let harmonics get you down

In 1976, it was discovered that the bacteria causing Legionnaires disease, an atypical strain of pneumonia, had always been present in water, but it was the precise temperature of the water in heating, ventilation and air conditioning systems that facilitated the bacteria’s maximum reproduction levels. This is just one example of the unintended consequences of technology.

A similar and more recent story comes from the world of industry and features the growing problem of harmonic currents and utility level voltage distortion, as a result an increasing number of non-linear loads in industrial and commercial environments. Here, John Mitchell, global business development manager of CP Automation, shares his top tips for companies that want to commission or replace harmonic filters.

Active versus passive

The first thing you should decide is whether you need a passive or an active harmonic filter. The traditional option is an electro-mechanical or semiconductor controlled passive filter, used to minimise power quality problems in the network. These filters operate mainly on a fixed basis and are tuned to a harmonic order close to the order to be eliminated.

Often new equipment is specified to meet a THID%, but the problem for many plants is they do not know how bad their site is already. It’s almost like fixing a sticky plaster to a deep wound. Instead, companies should look at what is physically and commercially viable in the long term.

When making a decision, you can also consider a mixed solution. By fitting passive filters on many applications, you should be able to add a smaller active solution, which can save a lot of costs depending on the plant.

One drawback of passive filters is that they are most efficient when the load is operating above 80%.

On the other hand, active harmonic filters continuously monitor the network and inject exactly the right amount of compensation current when it is needed. The filter compensates the harmonic current or voltage drawn by each load. This allows current waveform to be restored instantaneously and lowers current consumption.

For installations in which current load changes constantly, active harmonic filters work best. They can filter harmonics over a wide range of frequencies and adapt to any type of load.

Regardless of what type of harmonic filter you decide to use, make sure it has the relevant UL certifications for the environment in which it's going to run. If unsure, you should always refer to an expert.

Holistic approach

Before commissioning a harmonic filter for your application, it’s important to assess the entire system, calculate the harmonics and size the right solution for your specific set up. It is not enough to look at one troublesome application individually; instead, you need to look at the plant or entire operation as a whole. Often what looks like the problem can actually be an effect rather than a cause.

Companies should identify and understand all the components installed on site when it comes to both linear and non-linear loads. They should also be aware of the transformer size and the rated short-circuit breaking current. Only after understanding the system in its entirety, can a company make an informed decision on what type of harmonic filter it needs, as well as what capacity and additional features the filter should have.

CP Automation recommends performing a survey of the plant and capturing as much information as possible over several days. After this initial analysis, we can recommend the most appropriate product and install it without significant disruptions.

After the harmonic filter has been live for a several days, another survey should be performed to check if all problems have been resolved. This ensures the product is appropriate and it gives companies real peace of mind.

The increasing levels of harmonic currents in industrial and commercial applications are certainly an unintended consequence of rapid technology uptake. Luckily, like the Legionnaires disease bacteria problem, the solution is simple, sustainable and inexpensive. Moreover, if you’re unsure of what harmonic filter your system needs, help is never too far away.

The road to energy efficiency starts here

Did you know the invention of robots dates back to XVth century? When Leonardo da Vinci explored the idea of the human body as a machine, he came up with a robotic knight - medieval armour designed with gears, wheels, pulleys and cables that allowed it to move its arms and legs. Premature inventions like this one populate the engineering landscape to this day, often when it comes to energy-saving technologies such as regenerative braking.

Here, Tony Young, owner director of CP Automation, explains how easy it can be to make industrial applications more energy efficient by using regenerative braking.

One solution suitable for many industrial applications, particularly in heavy engineering, transport, mining, the elevator market and other applications that involve a lot of braking and restarting is regenerative braking. When braking, an electric motor generates energy that can be used immediately in the local grid and thus reducing the draw from the mains supply.

In effect, this means turning your motor into a generator, converting mechanical energy into electrical energy, which can be fed back to the local network. The mechanism is extremely common in electric and hybrid vehicles where the energy is stored in the batteries and works particularly well in urban environments, where drivers tend to brake often enough to generate a lot of energy.

Lesser known applications of regenerative braking can also be found in industry. By using a regen unit like RevCon in engine test stands, transmission, escalators, power plants and many other applications that use continuous braking, you can regenerate the braking energy of the driven system, and feed it back into the network.

Regen power can be sized to the application; for a 90kW drive, for example, a 30kW regen unit could be suitable - because it rarely brakes at full capacity. The capacity range of regen can vary anywhere between 4kW and 300kW – the higher the capacity, the bigger the savings and the faster the payback. A good regen unit should work with any AC drive and should be easy to retrofit to any inverter, irrespective of design or manufacturer, due to its non-software driven installation protocol - plug and play so to speak.

RevCon can use a feed-in tariff similar to the ones found on domestic and semi-commercial wind turbines, to allow companies to charge the electricity supplier for the excess returned power, should the building not use the energy locally.

So why isn’t regen braking used in more industrial applications? Although the cost of regen units has gone down significantly over the last few years, they are still much more expensive than some of their alternatives. Like many other technologies that were ahead of their time, regenerative braking is likely to increase in popularity in the next few years. To stay ahead of the curve, companies should investigate the benefits of the technology sooner rather than later.

ADF Power Tuning - low harmonic solution

Quality sunshine

EMC filter for solar power applications

Maintenance and repair specialist CP Automation now distributes and fits Roxburgh EMC's innovative high voltage, high performance three-phase EMC filter range. The KMF3420V is specifically designed for use with high kW inverters used in photovoltaic solar power applications.

Roxburgh's distributor of the year for 2015, CP Automation, can help customers integrate the filters along with compatible inverters into their solar power systems.

Roxburgh's electromagnetic compatibility (EMC) filters are fitted on inverters to minimise harmful electromagnetic noise that can damage electrical equipment or cause spurious malfunctions

The high voltage model of the KMF series operates at a voltage rating of 690V, significantly more than competing products that usually only work up to 500V. The innovation came about after a world-leading manufacturer of solar inverters got in touch with Roxburgh and asked it to develop an EMC filter that worked at 690V instead of 600V. The 690V model has the same footprint as the 600V, resulting in significant space savings.

The KMF3420V works at a temperature rating of 65 degrees Celsius, as opposed to the industry norm, 50 degrees. This makes the filters perfect for the difficult conditions of photovoltaic power applications, which present high ambient temperature challenges.

"Renewable energy now provides approximately 18 per cent of global electricity generation," explained John Mitchell, global business development manager of CP Automation. “For that number to continue to rise, solar power generation and distribution needs to be as efficient as possible. That's why quality EMC filters are so important to the industry.

"Our KMF3420V was one of the first EMC filters to be rated at 690V in accordance with UL1283 Edition 6. Compliance with North American certification gives customers peace of mind globally and makes it easier to achieve local certifications for their finished products”

For more information about CP Automation's catalogue of Roxburgh EMC products, go to www.cpaltd.net. 

Think outside the box for cranes and hoists

Systems integration complexities in cranes and hoists market

When contemplating entering the cranes and hoists market, panel builders and system integrators need to think outside the box - not only laterally but vertically as well. Mainstream horizontal applications like conveyors cannot be shoehorned into the same category as cranes and hoists. Tony Young, owner and director of CP Automation explains the complexities of vertical lift applications. 

Cranes and hoists is a specialised market requiring expertise in variable speed drives (VSDs) and inverters, programmable logic controllers (PLCs), motion control, braking, safety systems and last but not least, best practices.

The latter is important when working at height and systems integrators need to be fully insured when taking on this specialised environment. They need to be ISO-registered and carry out risk assessments on all crane installations.

If one considers moving a heavy object on the end of a length of cable, there are lots of complexities involved, like using anti-swing program software for example, when setting motion ramps and profiles in an inverter or PLC.

The systems integrator needs to make sure that whatever the weight of the object, the crane or hoist should not be stopped so suddenly that the object starts swinging back and forth to the point of losing control and causing potential damage as well as delaying the actual hoisting.

This is not the same thing as a soft start because the problem is one of controlling motion along several axes at the same time. For example, where a load needs to be lifted from a ship while the boom of the crane is also rotating, the load is swinging around and needs to be slowed down correctly to avoid the crane operator losing control of the load.

A crane’s load suspended from a cable creates a pendulum that swings in motion. Anti-swing control calculates and compensates for this motion. The trade-off is between reducing load oscillations and transferring the load in a reasonable time.

Anti-swing software
In the past, before proprietary anti-swing software was available, this required considerable skill on the part of the crane operator. Controlling the load position and its swing may be implemented in a proportional derivative (PD) tracking controller to follow a prescribed trajectory.

Then, another controller may need to be added to the control loop to damp the load swing using techniques like time-delayed feedback of the load swing angle and an anti-swing fuzzy logic control. A mapping method used for generating the rules can be applied to mimic the performance of an expert crane operator.

Other functions may also need to be programmed in an IEC 61131-compliant PLC language like ladder diagram (LD).

By partnering up with electrical and automation companies, systems integrators and panel builders can increase their technical capabilities and understanding of the market. A good industrial automation supplier should be able to provide both in house and on site commissioning, servicing of inverters and ancillary products used for motors in cranes and hoists.

Systems integrators need to kit out workshops that are fully equipped to rapidly identify faults and components failures. They also need to employ experienced and highly trained engineers to provide both in-house and on site services for all types of drives. Furthermore, they should offer a complete industrial electronic service.

Training instructors need to be industry experienced engineers with current hands-on application experience, whose technical skills are annually assessed and updated. They should provide a comprehensive selection of first class industrial automation training products, assessment services and courses to meet customers’ changing needs.

So when designing panels for cranes and hoist applications, it pays to think outside the box. 

The race to replace - CP Automation helps Tata Steel replace legacy motor

Heavy industries often use electrical equipment older than the majority of their staff. That means when legacy motors, drives or control systems need replacing, finding the right balance between cost, power, energy efficiency and simply doing the job can be tricky. When Tata Steel wanted to replace a 40-year-old motor used in one of its pipe manufacturing facilities, the company worked with Rockwell Automation and repair and supply specialist CP Automation to find a solution that boosted overall production and energy efficiency. 

As a leading international steel manufacturer, Tata Steel capitalises on decades of experience and global capabilities to deliver pipeline solutions for challenging offshore and construction projects. The Hartlepool SAW (pipe) mill, located in the North East of England, has three manufacturing facilities with a combined annual production capacity of 440,000 tonnes of tubular products for the construction, engineering, energy and power markets.

The problem with old motors

At the very heart of the production process lies a powerful expander used to shape, size, and strengthen pipes. This unique machine is used only in pipe making and is the only one of its kind in the UK.

The expander’s large gripper car move the 12.5 m long pipes over the expander head and, until recently, a 40-year-old DC motor drove the gripper car. The motor used an obsolete control system that was not very accurate and, as a result of the low speed, it often caused bottlenecks in the production process.

Tata Steel was using a 40-year-old DC motor to drive the gripper car that moved
the 12.5 m long pipes over the expander head

Because of its age, the DC motor also required frequent maintenance and had high-energy consumption rates. As the motor was obsolete, the spares and DC drives it required were hard to come by, so the entire application had a serious reliability issue.

To reduce the risk of costly downtime and make the entire production process more efficient, Tata Steel asked Rockwell Automation for advice on a replacement motor and drive for the application. In turn, Rockwell Automation enlisted the help of repair and supply specialist CP Automation for the high power requirements of the drive project. CP Automation worked alongside Rockwell Automation and Tata Steel to identify, deliver and install a replacement motor and drive for the application.

The right fit

Tata Steel shared the mechanical drawings and old drive system drawings of the application with Rockwell and CP Automation and supplied a set of twelve specifications for the new system.

“The sheer size and scale of the application made it a challenging project, but the additional requirements for better energy efficiency and accuracy meant an off-the-shelf motor and drive system simply wouldn’t suffice,” explained John Mitchell, global business development manager of CP Automation. “To fulfil the requirements, we worked with Spanish motor manufacturer and partner VASCAT to produce a bespoke 150kW motor, at 300Amps and with a speed of 1070 rpm. Rockwell supplied the 250kW Powerflex 755 inverter drive with CIP motion function and associated PLC.”

VASCAT produced a bespoke 150kW motor, at 300Amps and with a speed of 1070 rpm

VASCAT designed the motor especially for the application with customised windings, and delivered it in time for the summer shutdown. The motor had to be about the same size as the previous one and come with pre-installed cabling so it was easy to position on the existing motor plate bed. The new motor is 1m long by 0.75m wide and weights 853 kg.

CP Automation worked with its distributor Routeco to supply the equipment in time for the summer shutdown. The close collaboration between the different parties involved meant the project timeline started at the beginning of 2015 and the new drive system was up and running at the end of August.

“One of the challenges we faced during the project was that initially we didn’t think there was any need for a regenerative braking unit,” explained Tony Brown, electronics engineer Tata Steel. “However, when the motor, drive and PLC were up and running, the stop and start function wasn’t as fast as we wanted it to be, partly because of the sheer size of the motor. The drive kept tripping, so we needed to find a solution.

“CP Automation suggested introducing a Revcon regenerative braking unit to make stops and starts more seamless and to increase the speed of the application, thus making the pipes move faster. This is where we really reaped the benefits of the new equipment, both in terms of speed increase and energy efficiency.”

Regen unit REVCON RHD for continuous braking

Clear improvements

“Perhaps one of the most significant improvements in the process came from the accuracy of the new servo drive system,” explained Brown. “The new drive system allows us to position the pipe within 1mm accuracy, whereas the old DC system’s accuracy was closer to 50mm. This increased level of accuracy coupled with a ten per cent improvement in speed has resulted in productivity improvements throughout the application.

“The success of the project convinced us to replace the auxiliary drive system on the expander,” continued Brown. “We have already discussed the details with CP Automation and Rockwell and are hoping to upgrade the auxiliary drive unit during the 2016 summer shutdown.”

Bringing legacy systems up to speed

In an era of Industry 4.0 and smart factories, the temptation to fully replace an obsolete production line is high. However, this isn’t always the most cost-effective or productive approach. Sometimes it’s better to just replace the inefficient or unreliable parts of a system – and these are often the parts that work the hardest, like motors, drives or pumps. Each application is different, so the first step has to be performing an audit to identify any sore spots.


If you are struggling to bring your obsolete production line up to speed, get in touch with CP Automation on +44 (0) 1724 851515 or on enquiries@euroservltd.net.

Roxburgh EMC Awards 2015 distributor of the year

Roxburgh EMC are delighted to name CP Automation Ltd, as their 2015 Specialist Distributor of the Year.

After remaining a distributor of Roxburgh EMC products for over three years, CP Automation, a supplier and repair specialist of industrial equipment, is now being awarded for their dedication to the Roxburgh EMC brand.

Tom Downing, Product Manager of Roxburgh EMC commented; “CP Automation stocks an extensive range of our industrial filters and they have gone from strength to strength since the beginning of our partnership. Their growth has enabled Roxburgh EMC to enter new markets and we presented this award to them in recognition of their commitment and effort. We have enjoyed working with CP Automation and hope to see continued success in the future.”

CP Automation stocks over 40 of Roxburgh EMC’s industrial filter lines, including the popular three phase filters, three phase and neutral products, plus, high current single-phase ranges. The team also comprises skilled engineers, who can offer technical advice that proves extremely valuable to customers.

"Since our partnership with Roxburgh EMC, we have been able to help our customers by solving their EMC issues, which makes it a great fit to CP Automation's portfolio," explains John Mitchell, Global Business Development Manager of CP Automation.

CP Automation specialises in universal peripheral equipment for variable speed drives as a core part of its offering to include dynamic braking resistors, external brake choppers, regenerative units, harmonic filters - both passive and active - line, motor, sine wave chokes and motors.

"Our decision to stock from 1A to 820Amps has given our customers the ability to win projects when they have been let down by their current suppliers due to lead-time issues,” continues Mitchell. “We work closely with OEMs in helping them design the right product into their application. Roxburgh EMC's manufacturing ability to design custom filters with brand labelling, as well as responding to time pressures, has also been key to our customers’ requirements."

Tony Young, Director of CP Automation Ltd, concludes; "The synergy to market between aspects of both businesses has resulted in this success utilising the key people in sales, marketing, engineering, procurement and manufacturing. We look forward to continuing the growth we have seen into the future."

Roxburgh EMC is a manufacturer of EMC solutions including EMC filters, EMC components and surge protection devices for a range of industrial applications. Roxburgh EMC was established in 1969 and is one of four brands of DEM Manufacturing; a division of Alpha 3 Manufacturing Limited.

For more details about Roxburgh EMC, please visit www.dem-uk.com/roxburgh.
For more information about CP Automation, please visit www.cpaltd.net.

Photograph (L-R) Louise Underwood, Accountant at CP Automation, Tom Downing, Roxburgh EMC Product Manager and Gary Cook, Internal Sales Engineer at CP Automation.