Variable Speed Drives and Energy Savings

September 9th, 2011 by pherniak

Industrial facilities consume large amounts of power throughout their operation. A major draw on this power is the HVAC system, compressors, and liquid pump systems. Approximately 65% of energy consumed in industrial situations is from motors. Reducing this overhead expenditure can ensure profit margins and energy efficiency. There is a great opportunity for savings here.


EG Energy Controls produce a system designed precisely for this purpose; the PowerMiser VSD. It controls variable speed drives for maximal energy savings. The turn-key system can be easily retrofitted to existing systems or incorporated into new industrial designs. In most cases, fan speed can be reduced by 25% for central HVAC systems without compromising air quality. The PowerMiser VSD uses a pulsed square wave signal to modulate the operation of motors. Pulse width depends on load size and desired power reduction; the system is designed specifically to not to stress motor windings (either thermal or electromagnetic stress). Additional benefits include more precise process control and soft starting. As well there is no need for energy wasting throttling systems; these inefficient systems include outlet dampers and control valves. There is also a voltage change filter (DV/DT) to prevent voltage spikes to motors not inverter rated. The system thus ensures maximum lifespan for all motors controlled by the system.


With control over rotational speed, comes control over torque. This means that a variable speed controlled AC motor can be comparable to a DC drive in terms of speed accuracy and quick torque response. The PowerMiser VSD offers dynamic torque control, with the ability to choose the torque level or keep it at constant levels. Processes involving rotating machines can be fine-tuned for energy savings and precision. The system can also be used to reduce demand during peak hours, saving more capital.  Industrial engineers and process control officers should take note of the system for its benefits and potential savings.


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