Design matters



When people think of shape and size design in engineering, they tend to think of people like Raymond Loewy, a 19th century American industrial designer who designed a wide variety of things such as sewing machines, the interior of Boeing aeroplanes, refrigerators and Coca Cola bottles.  They don’t generally think that power control units and the thyristors inside them are designed with their size and shape taken as an important consideration.  However, size and shape are very important when saving space saves money.

Loewy’s designs tried to achieve the ultimate in aesthetics, ergonomics, functionality and usability.  At CD Automation, we don’t spend too long worrying about the aesthetics of our thyristors and power controllers but we do think it’s incredibly important to get functionality and usability of our units right and that includes the size and shape.

As we’ve worked closely with our customers over the past 25 years or so, we realised what a major concern space was and we set ourselves to reducing the back panel footprint of our thyristors.  We did this because a smaller footprint saves cabinet space and, more importantly, minimises costs, because a smaller cabinet can be used to house the thyristor.

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Is Gas or Electricity the Best Way to Heat an Industrial Oven?

Industrial oven


Opinions are divided on the issue of gas versus electricity when it comes to domestic ovens.  Many people favour gas because it’s cheaper and they find gas ovens easier to control.  Funnily enough, with industrial ovens, gas is still cheaper as a fuel type but these types of ovens are actually much harder to control especially in precision applications.  As the uses for industrial ovens are much more varied than with domestic ovens, the considerations to take into account when choosing between gas and electricity are more complicated.


Electric heating is much more efficient. Even with modern burners there is a certain amount of wastage with gas supplied to the burner through pipes etc. With electric heating, you only use the amount required.  Add to this the fact that electricity is much easier to control and it’s easy to see that electric industrial ovens can be more energy efficient than gas ones.

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Thyristor Firing Types Explained


When deciding which thyristor is best for your process, you will need to Thyristors CD Automation 2consider a number of factors such as the load amperage and type, but a major one is which firing type you need.  This sometimes confuses people as they think that thyristors just switch power on and off which is essentially true but at what phase of the cycle they do this can have a huge impact on their usage. 

There are two main types: zero voltage crossover firing and non-zero voltage crossover firing.  Which one will be most appropriate for your operation will depend largely on what level of control you require, the type of load and heating elements and how much Radio Frequency Interference (RFI) you can tolerate.

Zero Voltage Crossover Firing

This type of thyristor only gates when the voltage across it is zero.  It stays on once triggered until the conducted current drops to zero which occurs naturally every ½ cycle in an AC waveform.  They have two firing types: ON/OFF and Time Proportioned on/off which is sometimes called Burst Firing.

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An Introduction to Thyristors

electrical elements

Often confused with transistors and sometimes referred to as silicon controlled rectifiers (SCRs), thyristors perform vital functions in AC and DC circuits and are used extensively in industry due to their robustness and reliability. 

Thyristors were invented in 1957 but are still used today to switch electric currents ranging from a few milliamps at tens of volts to thousands of amps at thousands of volts.  At CD Automation, we supply a full range of thyristors for all kinds of applications.

What is a Thyristor?

Thyristors are made up of four layers of semiconductors, rather than three like a transistor, and the most common variety have three connectors like a transistor.  Current is controlled by a gate between the positive and negative terminals.  A small current at the gate triggers the larger current flowing between the terminals.  The gate can be switched on and off very quickly and there are no moving parts involved which gives the thyristor its robust qualities.  They can’t be used as amplifiers like transistors can but can control much higher electrical currents.  As they conduct current in one direction only, two need to be used back to back to work in AC circuits.

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What are the benefits of using a motor soft starter?


AC motors play a large part in producing pretty much everything. Starting them up is as easy as flicking a switch but what is the cost? Running these machines can be expensive in a variety of ways including the electricity bill, the maintenance and the production time lost due to downtime.

Fortunately, using a motor soft starter can reduce these expenses by limiting the amount of energy expended when the machines start, lessening the stress on the mechanisms as they start up and reducing the strain on the electrics. AC Motor Soft starters provide all these benefits and cost around a quarter to a third less than a variable frequency drive.

Energy Reduction

Did you know that most of the electric motors used in manufacturing are fixed speed, fixed voltage AC induction motors and these consume up to two thirds of the total electricity used in industry? One of the reasons they use up so much energy is because they draw additional current at start up and, not only does the sudden influx of power put strain on the machine, much of the power is wasted. Using a soft starter prevents the motors from drawing excessive power at start up so reduces the overall amount of energy used, thus reducing companies’ energy bills.

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Thyristor Controllers Speed Up Production for McLaren

Improved controls for paint drying system drives sports car production forward

Thyristor power controllers from CD Automation have been instrumental in significantly improving production efficiencies for Woking-based luxury sports car maker McLaren Automotive. From modest beginnings the organisation has grown into a world renowned and respected brand and a byword for advanced technological excellence, intelligence and attention to detail. Drawing on 50 years of racing success McLaren has created some of the most iconic and exhilarating high performance road cars the world has ever seen.

Not surprising then that in the manufacture of its sports cars McLaren demands the very highest quality and reliability from every inch of its production line. When it experienced problems in the paint finishing section with a specific colour that was proving increasingly popular with customers, the company explored solutions that could be implemented in the shortest timeframe possible while providing longevity and consistency.

McLaren’s 200mph British supercar dubbed 'an F1 car for the road'

McLaren’s supercar dubbed ‘an F1 car for the road’

The paint in question was taking much longer to dry than other shades and hence holding up the entire production line. When you are manufacturing cars that will set the customer back hundreds of thousands of pounds, this is a situation that demands immediate attention.

Furthermore, the paint is very much part of the overall package and an integral part of the build and assembly process of the chassis. So while it may be the last procedure to be applied after months of design, development, construction and assembly it is an extremely important element of the finished car.

Customers can choose bespoke paint, trim and colour options – McLaren’s team will match anything they want and advise on combinations, producing flawless work 100% of the time to each specification and turning projects around within sometimes very tight deadlines.

A long-standing customer of Panther Engineering, McLaren approached the company for a solution to accelerate the drying time, confident in their knowledge and expertise in the design and build of control systems. They designed a bespoke package that provided additional heating and force drying applications using Thyristor controllers supplied by CD Automation. This comprised 3 units of the Three Phase REVO S Thyristor (SCR) Power Controller each suitable to switch 210 Amps at 480Vac, resistance type load and utilizing Burst Firing technique; all protected by extra-rapid quick-blow semi-conductor fuses. A compact and self-contained unit, the REVO-S offers exceptional reliability and low maintenance, meeting the high spec required by the end customer.

“Thyristor control is the most economic and reliable means of controlling large amounts of electrical power,” explains CD Automation’s Jez Watson. “It results in reduced waste and energy consumption but more importantly, improves process consistency and reliability in extremely harsh environments such as McLaren’s paintshop.”

Production facility at McLaren's Woking site

McLaren’s Woking production facility 

Temperature control was a crucial factor in the drying of this special paint finish; requiring accuracy to within
+/-1 degree to produce the desired result and the REVO-S has successfully eliminated the problem, speeding up production and improving efficiencies for McLaren.

CD Automation has supplied Panther Engineering with three similar units for previous projects.

“We have worked with CD Automation for several years and were more than happy to recommend their products to our customer,” explains managing director Duncan Roberts. “Maintaining productivity throughout the installation was vital for McLaren and as such we needed to be 100% confident of quality and reliability.”

In addition, retrofitting McLaren’s paint drying system without holding up production presented a challenge for Panther with a window of just 1 week scheduled to make the final changeover.

Panther Engineering received positive feedback from McLaren as the company quickly experienced significant improvement in their daily production runs which far exceeded expectations – keeping their sports cars and their business well on track for success and ensuring each customer gets the finished result they rightly expect.

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Electrical Noise – Something You Will NOT Want To Hear

Electrical interference is a common issue in almost all industry applications. It is made from very high and very low frequencies that enter devices making them perform abnormally.  This article looks at the common symptoms that your processes might be presenting and also the solution to eliminating electrical noise.

Electrical Interference Example

Electrical noise can plague your processes without you even realising it. This cloak and dagger mischief is created from harmful frequencies that can be produced from almost anything electrical, with most common sources being:  inverter motors, phase angle firing thyristor power controllers or by more everyday items like mobile phones or wireless communications. This production of interference can then be absorbed, radiated or conducted, then fed into electrical instruments.

Some of the common symptoms you may notice in your process may be faulty sensor readings, flickering control screens, random system lock outs and alarms being suppressed. The worrying thing is some devices may not show visual signs of interference affecting them but inside they can be degrading and unproductive.

Electrical interference effectively erodes the internal circuits and components of your electrical device that in turn can reduce efficiency and productivity. In time these devices may not function at all. With ambiguous results and no clear way to rectify the situation, many people ignore the inconveniences and some may even turn a blind eye. This however can become an expensive exercise with higher maintenance costs to replace faulty devices and possible long periods of downtime while repairs are being made.

But there are ways and means of ensuring your processes are protected so you don’t face that scenario.

The solution comes in the form of a range of high quality power filters designed to drastically reduce interference so that your electronics run flawlessly. Our EMI & RFI single & three phase power filters are not just a cost effective solution but with their compact design, take up the minimum amount of space possible. Add an array of connection styles to reduce the hassle of installation and you have the perfect solution to improve your electrical performance.

These Filters are suitable for both immunity filtering (protection from interference entering devices) and emission filtering (preventing emissions being released).

You can save yourself long-term aggravation and maintenance costs by taking the quick and easy solution that is guaranteed to produce results, meaning you can enjoy long-term savings and reliability.

If you would like more information on electrical noise why not request our free special report, simply send an email with ‘Special Report on Noise’ as a header and we will do the rest.  Alternatively see our power filter product range here

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Solving The Thyristor Puzzle

After analysing the questions our clients ask most frequently, we decided to put together a range of comprehensive graphics that explain the applications, features and benefits of some of our most popular products. The first on our list is the thyristor. To make the technology more accessible, we’ve created a friendly infographic. We’re also preparing  a start-up cheat sheet for commissioning and installing thyristors.

The UK manufacturing sector employs 2.6 million people and accounts for almost 50 per cent of the country’s exports. The complexity of manufacturing processes has significantly increased over the last decade, with technologies like intelligent automation, robotics and 3D printing putting extra pressure on manufacturers everywhere. Although new technologies have the potential to make manufacturing more lucrative and energy-efficient, older generations of electrical equipment are still at the very heart of the process and essential for those new concepts to operate effectively. One such example is thyristor power controller.

“A thyristor is the most reliable control method when it comes to applications that use large amounts of electrical power,” explains Jez Watson, managing director of CD Automation UK. “The benefits of using a thyristor power controller go beyond reducing waste and energy usage. The equipment allows users to improve process consistency and reliability in very harsh environments.

“CD Automation wants to help its clients make informed purchasing decisions. Our new infographic allows customers to quickly identify the applications and benefits of suitable products.”

Thyristor power controllers can be used in any process using electric heat, including welding, ovens, kilns, boilers, furnaces or environmental chambers. Designed to handle loads of up to 3 Mega Watts , thyristors are highly reliable and only require very low levels of maintenance.

Thyristor applications

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De-geeking The Gobbledegook of Thyristor Control

There may not seem to be much to associate the Teutonic deity Wotan with our experts here at CD Automation, but like Wotan’s ability to summon up a magic ring of fire, we’re experts on thyristor firing methods.

To the uninitiated, these methods may seem like magical spells, but CD Automation has mastered them all, from zero crossing and phase angle to soft start with burst firing. We do our best de-geeking the entire gobbledegook of thyristor control for our customers world-wide.

“CD Automation has been dealing with thyristor applications for 27 years, and in this time we’ve learnt how to tame the fire in this magical electronic device,” explains Jez Watson, managing director of CD Automation UK.

“If you have peak current in the mains supply, you generate flicker depending on how strong the supply is. This manifests itself in both domestic and industrial applications as flickering lights.

“If you start a large industrial motor, the lights will dim briefly because of the large peak inrush current. Preventing peaks on the mains supply can be achieved by using phase angle as a firing method for example.”

Thyristor dimmers switch on at an adjustable time (phase angle) after the start of each alternating current half-cycle, thereby altering the voltage waveform supplied to light and changing its RMS (Root Means Square) effective value.

The advantage of phase angle mode is that its continuous – it does not generate peak current, continually reducing true and RMS voltage to control an electric load from zero to 100 percent without interruption.

The resistance of the tungsten element in a lamp when cold can be as low as one twentieth of its nominal operating load, which translates to 20 times the nominal current when it is first switched on.

With industrial tungsten heating elements and other heating elements made of carbon and molybdenum, the resulting mains flicker is something electrical grid suppliers very much frown upon. In fact, European directives have banned equipment that produces such flicker. Phase angle is a soft starting method similar to that used on electric motors to avoid current peaks.

Every advantage has a disadvantage, however. In this case, phase angle generates harmonic disturbances and reduces power factor – something else grid suppliers dislike equally, especially in hospitals and chemical processing facilities where sensitive instruments can be affected.

To prevent such disturbances you need to use large, heavy and expensive electric filters in the 150-550Hz harmonic range. At such low frequency you need large wound component ferrite inductors.

For example, a filter for a 75kW phase angle load will weigh about 55kg. Otherwise you can only use phase angle for a short period to prevent inrush current, and then switch to burst modulated firing mode.

This is used for infrared lamps between 500W and 1kW, the tungsten elements of which are typically heated from 500-700 degrees centigrade and used for heating glue, drying paint or blowing a bottle using a small lump of plastic.

When a bank of eight infrared lamps for example need to be modulated from 50% of full load power, then a load manager may be needed to avoid all lamps coming on at the same time and causing electrical disturbances. CD Automation’s REVO PC provides effective power control of inrush current to minimise load current taken from the mains supply.

The advantage of burst firing is that it doesn’t generate harmonics. Starting at zero voltage, it ends at zero current crossing, so if current is not synchronised with voltage and goes to zero, burst firing stops.

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Storms Whip Up Safety Concerns

‘They’ say that lightning never strikes twice. However, by the time you finish reading this sentence, the combined product of some 2000 storms raging at any given time around the world, will have produced in excess of 400 lightning flashes on planet Earth. 

It seems that ‘they’ didn’t live in the information age. The global population is now over seven billion, and the improving demographic transition of less economically developed countries, means that this is rapidly increasing, expected to reach eleven billion by the end of the century.

This population growth has highlighted the fundamental economic problem; of having seemingly unlimited human wants and needs, in a world of limited resources. This scarcity is becoming increasingly evident in traditionally prosperous countries, prompting people to search out and inhabit more geographically remote regions of the world.

Over the last few decades, this economic boom has fuelled the growth, development and industrialisation of previously unstable and climatically challenged regions.

And therein is the problem. Although industrialisation has changed, product design and development, as well as the associated legislation and control, is still playing catch-up.

Products and electrical components designed for use in western countries have been traditionally optimised for moderate weather conditions. This is reflected in the narrow operating temperatures, minimal voltage fluctuation protection and low thermal shock tolerance.

As organisations internationalise, they are beginning to build manufacturing facilities in previously uninhabitable regions, which exhibit severe meteorological and geological activity, meaning modern components are required to face often harsh environments.

Here at CDA we have addressed this problem in-keeping with our mission to go above and beyond customer expectations. We have recently launched a new range of Lumel certified products, tested to EN61010 international standards.

EN61010 is broken down into four categories. CAT (I) looks at electronics such as smartphones, laptops and tablets. CAT (II) includes household and workshop equipment such as refrigerators and drills. CATIII is what we’re interested in and CAT (IV) refers to utility level devices used on the mains power supply.

Under CAT III, customers can dabble in all industrial electrical equipment, from meters and analysers to transducers and controllers, resting assured that it has been tested to the highest standards.

Current industry practices are often risky, with CAT II rated devices being used in applications designed for CAT III ratings. This is often dangerous as under rated equipment may combust in application.

The legislation ensures that the equipment design and methods of construction provide adequate protection to the operator and the surrounding area against electrical shocks and burns, which can result from lightening strikes and surges, as well as protecting against mechanical hazards, excessive temperature and the spread of fire from the equipment.

The standards ensure that equipment is safe to be used both indoor and outdoor, at altitudes up to 2000m, and at temperatures between minus five and forty degrees. In addition to this, equipment must operate in humidity of 80% at 31 degrees and 50% at 40 degrees.

The most significant protection offered for bad weather regions is the ability to tolerate mains supply voltage fluctuations of plus or minus 10% of nominal voltage, as well as minimising the effects of radiation from laser and ultrasonic pressure sources.

So the next time you’re caught up in a storm and you witness the dramatic effect of a lightning strike, it’s probably best that you don’t stick around to find out whether it strikes twice. As long as your equipment is certified you don’t need to worry!

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