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Motor efficiency evolution

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In an era where efficiency is in the spotlight, manufacturers are constantly looking for ways to reduce energy usage. Katherine Crichton looks at how overall system efficiency is providing a solution.

ON December 3, 2007, Prime Minister Kevin Rudd made an international commitment to ratify the Kyoto Protocol, and on March 11 this came into effect.

Under Kyoto, Australia has set a target to reduce greenhouse gas emissions by 60% on 2000 levels by 2050.

With energy consumption a significant contributing factor to climate change, industry has been increasing under pressure to better manage and reduce energy usage and greenhouse gas emissions.

The Australian Greenhouse Office (AGO) introduced MEPS (Australian Minimum Performance Standards), governing electric motors, in 2001, revising the Standard in 2006, to what is commonly known as MEPS 2, which specified more stringent levels of motor efficiency.

This focus on energy efficiency in electric motor and and increasingly the usage of Variable Speed Drive technology has led to increased mandatory and voluntary improvements in the actual motor technology itself, but as Sean Richardson, Product Manager — Automation, WEG Australia notes, these improvements can be taken further in regards to entire system efficiency.

“For a long time we have seen the various benefits delivered by technologies like PID control loops in respect to the efficiency of motors used to control fans, and pumps with Variable Speed Drives (VSDs) where the process demand is measured and matched to the motor and drive output.

“Now we are also seeing developments in the actual software control of the drive with respect to the motor itself which in effect combines the system and component development,” Richardson explained.

“This is yielding real and measurable benefits to the customers through efficiency gains and at the same time delivering better performance of the motors when used in conjunction with this software based technology,” he said.

“In the past when there was a demand for high torque at low motor speeds, users who had a traditional motor and drive system were forced to either derate the motor (meaning they are literally paying more to buy a bigger motor) or had to use a forced ventilation kit.

“In many instances, the forced ventilation kit costs more than the electric motor itself, always requires additional installation work and will use additional energy to run.

“We eliminate this wastage by using utilising this technology.”

Optimising efficiency

As well as improved software control of the drive, there are also other elements of the motor system that can improve overall operating efficiencies.

Daniel Vera, MD of Australian Baldor also highlights the benefits of using an ‘entire system efficiency’ approach (or what he calls system optimisation) particularly in relation to motors and pumping systems.

“System optimisation is the evaluation of systems to determine how well the equipment is matched to the system.

“While there are certainly improvements in efficiency and savings in operational costs to be gained from the use of premium efficiency motors, the potential rewards are usually much less than those available from optimising the pump and system which rely on the power provided by the motor,” he said.

“For many industrial facilities, the energy consumed in pumping fluids comprises a large fraction of the overall facility electricity usage, though many operators of pumping systems are often not aware of how effectively the energy required to pump the fluid is being used,” he said.

“In many cases, if these pumping systems are unable to meet their functional requirements, a large part of the plant - or perhaps the entire facility - will be affected.”

Vera advises any effort toward reducing energy consumption and cost has to take the entire energy flow train into consideration.

“By evaluating the total system and matching the equipment as necessary to maximum system efficiency, the end result will provide optimum system reliability, reduced maintenance cost, energy savings and reduced down time.”

Towards the future

In developing a ‘whole of system’ approach to motor and drive efficiency, both Richardson and Vera stress communication and collaboration with system suppliers and manufacturers is key to achieving optimum system efficiency.

“Manufacturers can use motors drives more efficiently by knowing how the system is supposed to operate,” Vera told Manufacturers’ Monthly.

“This is the one biggest area where manufacturers and end users must work together to develop the entire system solution.”

For Richardson, education is also a vital part of achieving the aim of total system efficiency and he says simply legislating a standard such as MEPS and MEPS 2 on individual components is not enough.

“We need to educate the customers, the market in general and our policy makers in government so they can see that energy efficiency gains need to be based on a holistic approach.

“You need to make sure that the market not only is forced to look at change but wants to embrace the changes required to realise further efficiency advantages, Richardson said.

“In respect to energy efficiency, if we as suppliers to industry, are able to provide answers to the issues at hand in conjunction with a market that is actively seeking solutions, collectively we can arrive at a successful solution in regards to achieving true energy efficiency.”

Baldor Australia 1300 225 367

WEG Electric Motors Australia 03 9765 4600


 

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