At Hanover Fair ABB presents verified efficiency curves for its motor-drive packages, which means that investment payback times can now be calculated realistically. Accurate efficiency curves will be a major benefit in pump and fan applications, and will support efforts to cut energy costs and reduce emissions.
ABB, the leading power and automation technology group, has become the first manufacturer in its field to provide efficiency curves for standard, off-the-shelf motor-drive packages.
In the past, users of VSD (variable speed drive) controlled motors could only roughly estimate the energy consumption of their equipment. VSDs can operate motors over their full speed and torque ranges, and overall energy consumption is determined by the efficiency of the entire motor-drive package. By contrast, efficiency data has normally only been available for motors, and only at certain load points (100 per cent and usually 75 per cent respectively 50 per cent of rated speed and load). The same approach is taken by the International Efficiency (IE) classes, which specify motor efficiency only at full speed and power with a sinusoidal supply.
The new package efficiency curves from ABB cover the entire speed range, and will be particularly useful in pump and fan applications. In these systems the motor speed is generally adjusted to match the needs of the process, and – as pumps and fans are quadratic loads – the efficiency performance is very different from operation at nominal load.
Efficiency curves based on actual measured values
In ABB’s view the only reliable way to verify motor-drive package efficiency is by measurement. Using advanced equipment, ABB has tested standard, off-the-shelf drives and motors by accurately measuring how much electricity is fed into the drive and how much torque is produced by the motor. This represents a significant advance in efficiency measurement, as even the IE class levels are determined from motor losses rather than actual, measured efficiency based on output shaft power.
The efficiency curves will help motor-drive package users to reduce their energy consumption and meet their environmental commitments. They will be initially available for ABB’s SynRM (synchronous reluctance) motor-drive packages.
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