simo Motor Summarizes Common Misunderstandings in Motor Energy-Saving Retrofits for High-Energy-Consuming Enterprises
High-energy-consuming enterprises often fall into misunderstandings during motor energy-saving retrofits due to cognitive biases regarding technical principles and system characteristics, mainly in the following three aspects:
Many enterprises hold the cognitive misconception that "replacing with a high-efficiency motor equals energy savings," believing that high-efficiency motors naturally lead to lower electricity bills. However, the motor system is a complex whole, and the motor is only one part of it. If the motor does not match the load (e.g., "a large horse pulling a small cart" or "a small horse pulling a large cart"), the energy-saving advantages of high-efficiency motors cannot be realized.
For example, an enterprise replaced a motor for a water pump operating at only 30% load capacity with a Class 1 energy-efficiency motor. However, because the motor's power far exceeded the actual demand, it operated under low-load conditions for a long time. The design high-efficiency range of high-efficiency motors is mostly between 70%-100% load; under low loads, their efficiency can actually be lower than that of a suitably matched standard motor, ultimately leading to increased energy consumption instead of a reduction. This practice of "emphasizing the motor itself while neglecting system matching" renders the high-efficiency motor merely a "showpiece."
(II) Over-Reliance on Frequency Conversion Technology
Variable frequency technology, widely applied in the energy-saving sector for its ability to dynamically adjust motor speed, may conversely increase energy consumption if implemented indiscriminately. Some enterprises believe that "installing a frequency converter alone will save energy," overlooking the operational characteristics of the equipment.
For equipment with stable loads and no need for frequent speed regulation (such as constant-flow chemical reactor agitator motors), adding a frequency converter introduces the converter's own energy consumption (approximately 3%-5% of the motor's power), directly increasing the total system energy consumption. Simultaneously, compatibility issues between the frequency converter and the motor may cause harmonic interference, affecting equipment lifespan. Furthermore, the upfront investment for frequency conversion systems is relatively high. If the energy-saving effect is not significant, the enterprise's return on investment decreases substantially.
Many enterprises focus excessively on the initial investment cost, viewing "energy-saving retrofits as an additional burden," and tend to choose low-priced, low-quality products, neglecting long-term operational costs. A textile enterprise, aiming to reduce initial investment, opted for inexpensive, low-efficiency variable frequency motors. Although this saved 10% in procurement costs initially, during operation, the motor efficiency was 5% lower than the standard value, and the failure rate was high. Calculated based on its 24-hour operation, the enterprise incurred approximately ¥80,000 in additional electricity costs annually. Within three years, the extra electricity costs far exceeded the initial savings, not to mention production losses due to downtime for repairs. This approach of "picking up the sesame seeds but losing the watermelon" runs counter to the long-term goals of energy-saving retrofitting.
