Water-cooled motors suit tight spots

ABB launched a new range of low voltage water-cooled motors in IEC frame sizes 400 and 450, extending the water-cooled offering up to 1100 kW.

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ABB launched a new range of low voltage water-cooled motors in IEC frame sizes 400 and 450, extending the water-cooled offering up to 1100 kW. The new M3LP motors are more efficient and offer a wider range of optional variations than previous water-cooled models.

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Water-cooling dissipates more heat than air cooling, enabling water-cooled motors to provide more power than air-cooled versions in the same frame size. This makes them especially suitable for use in tight spaces and difficult environments. The efficiency of water-cooling is also maintained at lower speeds, which is important in constant torque applications. These advantages make the motors especially suitable for water and wastewater pumping applications.

M3LP motors have steel frames with channels for the cooling water around the stator core. The new design is modular, allowing customers to pick and choose from a wide range of options. For example, four levels of protection are available up to IP56. There are five possible bearing configurations and a similar number of shaft and rotor alternatives.

ABB water-cooled motors are rated from 75 to 1100 kW and are designed for voltages of up to 690V. They are available with between 4 and 8 poles. The cooling medium is water of tap water quality at up to 5 bar and 40 degrees Centigrade; higher temperatures may be permitted by arrangement with ABB.

ABB Limited
Daresbury, Warrington, Cheshire, UK

Enquiry No. 100

Sodium hypochlorite handling pump prevents vapor lock

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Watson-Marlow Bredel, the leading manufacturer of peristaltic pumps, announces the 520 Series peristaltic pump for Sodium Hypochlorite handling, ideal for use in the environmental industry. The combination of tube elements and pump head design allows the 520 Series to be utilized in the accurate metering, dosing and transferring of sodium hypochlorite, often used in the purification of wastewater and the disinfection of drinking water.

Entrained gas, often generated by the hypo, is pumped with ease, eliminating the occurrence of vapor locking that prevents conventional pumps from functioning properly. The 520 Series contain fluids within the tube at all times and never allows the sodium hypochlorite to come into contact with the pump mechanism, ensuring dependable, accurate fluid handling at all times. This helps provide predictable life costs for the pump, as the tube is the only part that will need replacing. The 520 Series pumps and patented LoadSure elements guarantee correct loading every time, as well as easy one-minute maintenance with no snaking, twisting or pinching.

Every Watson-Marlow Bredel peristaltic pump is an inherent metering pump with repeatability at 99.5%. Many models include integral digital drives and displays in washdown enclosures. These self-priming pumps accommodate flow rates from 0.1 microliter to 350 gpm and are extremely durable, withstanding pressures up to 232 psi. There are no internal universal joints, valves, dead corners or glands to impede flow and these pumps are reversible for back flushing lines. They can also run dry indefinitely without damage and provide up to a 30-foot suction lift.

Watson-Marlow Bredel Pumps
Cheltenham, England, UK

Enquiry No. 102

Simocode Pro V reduces MCC application costs

Siemens Automation & Drives launched new product innovations with further developments of their new ‘Intelligent’ motor control and protection system, Simocode Pro V.

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In water treatment and wastewater plants Simocode protects and controls AC motors in various applications such as pumps and ancillary drives. Typically in this industry sector fixed pattern MCC’s are used to house all the motor starters and PLC control systems. Using Simocode Pro to protect and control each starter offers significant benefits in terms of better plant utilization and a reduction in panel length by up to 30% leading to savings in civil costs and installation time.

Siemens Automation and Drives division added several features for the Simocode Pro V to broaden sector appeal of this product. New products in the range include a multi-line operator LCD panel which not only allows the user to see motor operating data, but also for maintenance personnel fault data and I/O status - All of which can be accessed without the need to use a PC. New calculation function blocks allow analogue values to be altered into real terms (such as flow) that are easily understood.

Customers can obtain power readings from each individual motor through the kWh (Kilowatt Hour) monitoring provided by the Simocode Pro V. Consequently, energy costs can be attributed to specific areas within a plant and power usage data is made directly available from the device without the need for conversion in the PLC.

The development of Simocode ES Graphic, for use within the Pro V range, provides an on-line graphic display function of signal flow within the program. Available as an add-on for Simocode ES Smart or Professional, this feature increases efficiency and understanding within the fault-finding process, even in complex systems.

Siemens Automation & Drives (A&D)
Nuremburg, Germany

Enquiry No. 101


ABB calls for greater transparency in motor data

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ABB is calling upon the electric motor industry to create greater transparency with its technical motor data by making available information that gives a clear indication of motor reliability, such as running temperature, alongside efficiency levels and motor noise.

While Steve Ruddell, ABB’s general manager for motors and drives in the UK, acknowledges that the number one reason why motors fail is through winding breakdown, closely followed by bearing failures. He believes that customers accept these failures too often without understanding the root cause.

“In our experience, we believe that many of these winding and bearing failures are a direct result of motors running too hot,” Ruddell said. “For example, you may be told that your bearing has run dry. While in some instances this may be down to a poor re-greasing regime, it is also possible that the motor was simply too hot and the grease degraded prematurely.”

Efficiency classifications, as defined by Eff1, Eff2 and Eff3, have helped customers recognize the difference between a poor energy efficient motor and a high energy efficient one, but ABB is concerned that the classification is also being taken as a measure of the reliability of a machine. Today Eff1 is perceived as high quality. The belief is that users pay a higher price for a higher efficiency motor and that the certification also indicates high quality and high reliability.

“This is just not the case,” Ruddell argued. “Our experience shows that there are some motors which achieve Eff1 status at the cost of significant drawbacks. These manifest themselves in many ways: increased running temperatures and excessive noise being a couple of examples.”

Ruddell proposed that “reliability” could be defined as the sum of efficiency plus temperature rise. He argued that each of these elements directly affect each other and therefore, the quality and reliability of a motor.

Eff1 is easy to achieve in all but the smallest frame sizes by simply increasing the amount of active material in the motor - more copper in the slots and smaller air gaps in the design. Yet the challenge is that the IEC34-2 sets tolerances for efficiency, which are quite wide. ABB fears some manufacturers are declaring efficiencies that are at the uppermost of the tolerance band, while delivering motors close to the lower tolerance level, or at worse outside this band.

Meanwhile, the temperature rise of a motor can also be higher than expected from an Eff1 motor. “Hold a thermal camera up to the motor and you can see how hot it is running.”

In the case of the windings, higher temperatures degrade the winding insulation more rapidly. While for the bearing end shields, higher temperatures can lead to premature degradation of the grease and increased re-greasing intervals.

“Clearly, the cooler the running temperature the better,” says Ruddell. “Lowering the temperature by just 10 to 15 degrees C can double the life of the winding yet most catalogues do not give this specific information.”

ABB has observed that some cheaper motors are generating more heat. The normal frame surface temperature in a high reliability motor running at full load can be as low as 60 to 80 degrees C. “Yet lower reliability motors often run in excess of 90 degrees C and have even been recorded at well over 100 degrees C.”

Temperature affects the re-greasing intervals of bearings. ABB assumes that bearings will run at 80 degrees C based upon an assumed an ambient of 25 degrees C. Should the bearing temperature increase by 15 degrees C, then the re-greasing interval should be halved. If the temperature decreases by 15 degrees C, the interval can be doubled. “The problem is that this data is not always highly visible, and so many engineers are probably not aware of this fact,” Ruddell said. “As a result if a catalogue states 10,000 hours and the temperature increases by 15 degree C, then the bearing would need re-greasing in 5,000 hours. But how is a user meant to know this? End-users with continuous process applications should ask their supplier to provide the winding and bearing temperature criteria from the type test reports.”

Temperature can lead to problems in other areas. More active materials usually mean more heat being generated. To keep the motor within stated temperature limits, larger fans are employed to provide more cooling air. Larger fans mean more noise.

“Remember, a 3dB increase in noise level is equivalent to a doubling of the audible noise of the motor,” says Ruddell. “So if, say, a 200kW motor is showing a 77dB against one showing a 70dB rating, then the 7dB increase in noise equates to the motor being about four times noisier. This should set alarm bells ringing. Higher noise levels could mean that the temperature is higher which affects the overall motor reliability.”

ABB say that getting the right balance between efficiency, temperature rise and noise will go a long way to lower life cycle costs, lowering running costs and increasing the overall reliability of an electric motor.

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