September 19, 2017

Automation: Fighting drought in Namibia


Bookmark and ShareFarmers in Southern Africa are feeling the impact of consecutive seasons of drought. The battle against drought conditions is continuous as the region struggles to maintain a reliable water supply. For this reason, CP Automation helped Rockwell Automation to provide the necessary power equipment to pump water from deep, underground boreholes.


Eco Projects was undertaking a 17 month project in Windhoek, the capital of Namibia, to alleviate a critical water shortage. Using boreholes, a deep, narrow hole made in the ground to locate water, the client pumped water to various reservoirs. This is to provide an accessible store of water for Windhoek. 

To power the pump system, Rockwell Automation delivered eight Allen-Bradley Powerflex 753 low voltage AC drives, varying from 250kW to 132 kW. However, to use these variable speed drives (VSDs) at depths of 150 to 250m, the company also needed to source sine wave filters. This is why the team reached out to CP Automation, which supplies and installs a range of sine wave filters for different applications.

Sinewave filters are used where variable frequency drives are installed with extremely long motor leads, as used with the depths of these boreholes. Due to an impedance mismatch, a portion of a high frequency wave is reflected back in the direction from which it arrived. When the reflected edges encounter other wave edges, their values add, causing voltage overshoots.

Sine filters reduce the edge steepness of the waves, meaning these edges can no longer accumulate. This prevents premature motor failure caused by damaging voltage overshoots.

"Without these sine wave filters, safety and power supply would be compromised," explained John Mitchell, global business development manager at CP Automation. "The filters eliminate high frequency content and voltage peaks generated by the variable frequency drive, thereby reducing motor heating and extending the motor life. If these waves were not converted, voltage overshoots could have halted this incredibly important project for the Namibian community."

"The long motor cable lengths meant the sine filters reduced parasitic capacitances," said Carlo van Heerden, Engineering Solutions Manager of Eco Projects. "The VFDs and sine filters created a winning combination, allowing the motor to run safely at continuously adjustable speeds, with adjustable torque for varying mechanical loads.

"Working with CP Automation, and joining forces in the way we have, has meant that we could carry out this project safely and efficiently, helping the people of Namibia access reliable water supplies, with long-term protection."

CP Automation may be carrying out a second phase on the current boreholes later this year, involving the installation of harmonic filters to reduce voltage distortion and to keep transformers cool and efficient for a long time. To find out more information about CP Automation's supply, installation and repair services, you can visit the website or call +44 (0) 1724 851515.

September 15, 2017

Sampling the depths


The oceans have been around for roughly 4.5 billion years. They cover 70 per cent of the planet, but we have yet to explore 95 per cent of their depths. In a bid to further investigate the wonders of the deep, scientists have recently researched mining rare metals — such as copper, zinc and gold — from volcanic rock on the seabed.

When a winch controlling a high-powered drill broke down on a ship mining samples off the coast of Japan, costing the company over $30,000 a day, the crew called maintenance and repair specialist CP Automation. Here, global business development manager John Mitchell discusses how CP Automation got the application running smoothly under strict time constraints.




Due to the location of the mineral rich area off the coast of Japan, sample extraction has to be planned 20 hours in advance, in accordance with how high wave crests were. The rougher the waves, the more the drill moves and the higher the risk of damage to an incredibly expensive piece of equipment.    

Just before the company deployed the drill for the first time, faults with the winch began to appear. Onboard engineers found the problem to be a DC BUS overvoltage issue caused by the brake chopper. The engineers attempted to alleviate the problem by replacing the brake chopper like-for-like, but their attempts proved unsuccessful. 

After calling a representative from the brake chopper manufacturer, they agreed to fly out as soon as possible. Unfortunately, due to time constraints, this meeting was cancelled, leaving the project losing tens of thousands of dollars every day and those on board no closer to rectifying the problem.

By the time the company contacted CP Automation, the drill had been out of action for two weeks and the crew were at wits' end.   

Winch and drill
The winch system controls the deployment of the drill to the seabed, which could be up to 3km from the ship. The winch also provides under tension — keeping the cable taught during payout. The brake chopper unit, rated at 400KW continuous 600A and 600KW, 900A at peak, dissipates the excess DC BUS voltage fed back from the motor.

If the winch cannot dump the energy created during this process into the braking resistors because the brake chopper has a fault, then the operator can't control the cable. This would result in the loss of a drill worth millions of pounds. It was therefore imperative that the brake chopper was reliable before the crew deployed the drill.  

Once the drill is in the water, the application provides active heave, compensating for the wave movement by automatically driving the winch in the opposite direction at the same speed to stabilise the drill.  The drill has to remain at a constant height from the sea floor so that it can clamp in position.  

Getting on board  
Because time was of the essence, CP Automation flew out to Japan as soon as we could. We powered up the application when the boat was docked and the brake chopper exhibited new sets of faults each time we tested. It was difficult to test under working conditions because we were unable to deploy the drill, which would work the winch motors. It was therefore impossible to tell if there were any electrical noise problems, which was our suspicion. 

CP Automation removed the existing brake chopper and fitted its own 100KW unit into the system. The fault did not transfer to our product, but reoccurred when we reinstalled the old unit.

Because the ship's crew identified a window when the sea would be calm enough to live test the drill, we were unable to carry out any more tests in dock.

Pushing off
The new brake choppers CP Automation installed were each a quarter the rating of the original unit. Consequently, we had to limit the max speed of the winch until it was possible to assess the current required during payout and active heave.

To fit the two brake choppers, we had to modify the control panel. This required us to split the DC BUS into two, with drives one and two on DC BUS one and drives three and four on BUS two.

This provided the system with an element of redundancy it did not have before. There was now the option that, should anything go wrong, the crew could operate the system with only two of the four drives.

After more tests in mild waves of 1.4m in height, the brake choppers were pulling 30A max per unit during active heave when the drill was at 750m from the ship. The DC bus level was maintained below 750VDC the whole time, which proved that the replacements were a proficient fix.

The client deployed the drill five times throughout the twelve hours and the system ran smoothly every time. As far as we could tell, there were no more issues relating to the brake choppers and the crew were able to extract all the mineral samples necessary.  

A shore fix
After careful testing, we proved that CP Automation's brake choppers worked in the drill application because, unlike the original unit, our brake choppers did not use external power controls. This meant they are not susceptible to external noise. The previous brake chopper had no electromagnetic compatibility (EMC) or harmonic filter installed, so the resultant electrical noise from the drill application and those around it, caused the brake chopper to fault.  

Scientists, fiction writers and film directors often refer to the oceans as the last frontier because of just how little we know about their depths. Indeed, deep-sea mining is still only in its infancy; scientists predict that minerals could be in abundance under our unexplored seas, albeit difficult to extract.

The drilling project CP Automation managed to revive is one of the first of its kind to sample valuable metals from tough volcanic rock. With the help of more research and investment, this method of mining could lead to a healthy flow of essential resources for years to come.  

September 12, 2017

High performance motors for silent operations

CP Automation now supplies Vascat's latest addition to its industrial motor portfolio; the new MAC QTW motor range designed specifically for low noise applications. This product launch will be particularly relevant to end of line testing, which relies on silent conditions as part of the analysis of a product.

End of line testing is a critical step in the production process. Defective products are separated from functional units by analysing the products vibro-acoustic behaviour pattern. This data provides crucial information regarding the condition of the product. However, any external ambient noise can corrupt this analysis resulting in unreliable results, which explains why a low-noise motor is required. 

"The MAC QTW motors have been designed specifically with test systems in mind," explained Xavier Palomar, sales and marketing manager at Vascat. "We want to increase reliability in end of line testing, and minimise false rejection of products."

"If businesses are rejecting perfectly good products because of false negatives, then money is going down the drain," added John Mitchell, global business development manager. "Confounding motor noise will no longer be an issue with this new range. We are pleased to be maintaining our long standing partnership with Vascat as part of this unique product launch."

MAC QTW motors are liquid-cooled, meaning they have higher efficiency compared with air-cooled motors. This further adds to the cost-savings already gained from reliable end of line testing. Added safety benefits also come from the IP23 protection rating and electrically insulated bearing within the motor.

CP Automation also supplies Vascat's MAC QW motors for general purpose industrial applications. If you are looking to upgrade an industrial motor for a test system, or more general application, CP Automation is available to supply and install this motor on location. For more information about CP Automation's catalogue of Vascat products, visit www.cpaltd.net of call +44 (0) 1724 851515. 
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