April 21, 2017

Increased efficiency for uninterruptable power supply


CP Automation now distributes and fits the REVCON boost converter module RSU as part of its range. This unit enables highly efficient uninterruptable power supply (UPS) of variable frequency drives (VFD). This compact power unit has huge cost saving implications for anyone that uses power loss ride through in their processes.

UPS systems provide an electrical supply that is converted from batteries when the mains supply is lost in situations such as brown outs, unstable supplies or emergency lift evacuations. The REVCON boost converter module RSU is set to change the way factories maintain their power supply.

"Traditional UPS systems lead the power to the VFD through the complete UPS application, even when power supplies are operating normally," said John Mitchell, global business development manager at CP Automation. "This results in unnecessary power losses due to rectification and invertation of the voltage.

"By adding a REVCON boost converter to the system, the UPS remains inactive when power supplies are working normally. This means the VFD is supplied directly by the mains, rather than having the middle-man UPS system causing unnecessary power losses."

When the mains power supply is down, the REVCON boost converter is activated and sets the voltage value from the batteries to the required level of the VFD. This maintains the power supply in the DC bus to the VFD, without any interruption.

This simple principle enables a highly efficient, yet inexpensive option for uninterruptable power supply to VFD drives. While conventional UPS systems have an efficiency of 90 to 95 per cent, adding a REVCON boost converter means the UPS setup will have efficiency greater than 99.5 per cent. This has huge cost saving implications for a range of industries that use power loss ride through in their processes.

CP Automation is available to supply and install the REVCON boost converter module RSU. For more information about CP Automation's catalogue of REVCON products, go to www.cpaltd.net.

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April 03, 2017

Common causes of electric motor failure


Modern electric motors may be more efficient and reliable than their ancestors, but they can still fail sometimes. Here, Martin McGuffie, service manager of Euroserv, sister company of CP Automation, explains the three common causes of electric motor failure and how maintenance staff can reduce the impact equipment failure can have on business.

How long do electric motors actually last before they break down? The answer is often disputed, with some manufacturers stating 30,000 hours and others suggesting they can power through for up to 40,000 hours. However, most manufacturers are in agreement that electric motors last much longer when maintained properly.

Understanding the state of an electric motor’s health requires a range of tools and techniques, as well as thorough record keeping and regular maintenance. This allows the engineer to identify trends or weak points more easily.


Weakened insulation

Nearly half of electrical failures in motors begin with weakening of the insulation around individual wires in the motor coils. This is often caused by thermal stress, contamination and movement of the winding due to the magnetic forces during start-up and shut-down of the motor.

Overheating can also cause the winding insulation to deteriorate quickly — for every ten centigrade rise in temperature, the insulation life is cut in half. Overheating can occur when the power quality is poor or when an electric motor is forced to operate in a high-temperature environment.

Contamination

Contamination is another one of the leading causes of motor failure. Contaminants include airborne dust, dirt or any abrasive substance that finds its way into the motor. When they come into contact with the motor, foreign bodies can cause denting of the bearing raceways and balls resulting in high vibration and wear.

Luckily, preventing contamination is fairly easy. Main sources of contamination include dirty tools, work areas and hands. Motors can also be contaminated by foreign matter in lubricants and cleaning solutions.

Engineers should keep work areas, tools and fixtures clean to help reduce contamination failures. Also, when laying out the space, companies should try to keep motor assemblies and operation areas away from grinding machines to reduce the amount of foreign bodies that might contaminate the motors.

Lack of maintenance

A well-planned preventative maintenance programme is the key to dependable, long-life operation of motors and generators. It also helps reduce unscheduled production stoppages or long repair shutdowns.

The first step towards preventative maintenance is understanding how often tests need to be carried out on the motor. This varies, depending on the age, condition and quality of the machine, as well as the environment it operates in.

Static tests are an easy method of identifying weaknesses within the motor winding. The tests focus on winding and insulation resistance, as well as turn-to-turn and phase-to-phase insulation condition. With the right equipment, these tests can be performed without taking the motor off site, thus minimising downtime.

Motor testing and analysis equipment, such as Euroserv’s SKF Static Motor Analyzer Baker DX, can survey all insulation and windings in AC and DC motors, coils and generators. During a site visit, Euroserv attends with the all-in-one tester, providing customers’ maintenance staff an analysis of the condition of the impedance, capacitance, phase angle, resistance, insulation and step voltage.

Motor failure can cause downtime, meaning companies can lose thousands of pounds every minute when operations are stopped. Instead of exposing themselves to downtime, customers should request regular motor testing and analysis, ideally every six months, to ensure their electric motors are healthy, efficient and reliable.

To find out more information about the SKF Static Motor Analyzer Baker DX, get in touch with Euroserv here.

March 20, 2017

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.


March 09, 2017

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.

July 08, 2016

Quality sunshine


EMC filter for solar power applications
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

June 10, 2016

Think outside the box for cranes and hoists

Systems integration complexities in cranes and hoists market
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.