Q1 What is a low-voltage high-power motor?
Low-voltage high-power motors refer to motors with low rated voltage (below 1000 V, usually 380 V or 220 V) but high power output. This type of motor usually has efficient energy conversion capabilities and can provide strong power support. While ensuring stability, it can meet the power requirements of high-power equipment. Compared with high-voltage motors, low-voltage high-power motors are safer, have lower manufacturing costs, smaller size, and are easier to install and maintain.
Q2 What are the main types of low-voltage high-power motors?
Low-voltage high-power motors are mainly of two types: industrial frequency and variable frequency. Low-voltage high-power industrial frequency motors refer to low-voltage high-power motors with a rated frequency of 50 Hz or 60 Hz. They are mainly used in scenarios that tolerate high inertia loads and frequent start-stops, and meet the needs of high-intensity continuous operations; low-voltage high-power variable frequency motors refer to motors with a frequency range of 0 Hz~50 Hz or higher, supporting wide-band speed regulation, and are mainly used in application scenarios that require variable frequency speed regulation.
In the past decade, the rapid development of AC speed regulation technology has expanded the application scope of low-voltage high-power variable frequency motors. Variable frequency speed regulation motors perform better than industrial frequency motors in terms of frequency conversion range, dynamic response, speed regulation accuracy, low-frequency torque, slip compensation, intelligent control, and work efficiency, and their development is also faster.
Q3 What are the characteristics and advantages of low-voltage high-power motors?
1. Low-voltage high-power motors have small frame sizes, compact structures, and higher motor power density. Usually, ordinary motors with power of 355 kW, 400 kW, and 450 kW all use frame sizes of 400. If low-voltage high-power motors are used, the frame size can be reduced to 355 to meet the requirements.
2. Low-voltage high-power motors are relatively light: Take the 355kW-2 motor as an example: the weight of copper, aluminum, and silicon steel is 6% less than that of ordinary motors, and the cost of raw materials is relatively reduced.
3. Low-voltage high-power variable-frequency motors are cheaper: The structure and electromagnetic scheme of low-voltage high-power variable-frequency speed-regulating motors are roughly the same as those of industrial frequency motors, but the insulation end cover structure of the non-shaft extension end of low-voltage high-power variable-frequency speed-regulating motors can reduce specifications, and the material cost is reduced by about 3% compared with industrial frequency motors.
Q4 What are the energy efficiency requirements for low-voltage high-power motors?
According to GB 18613-2020 “Energy Efficiency Limit Values and Energy Efficiency Grades of Electric Motors”: rated voltage below 1000V, 50 Hz three-phase AC power supply, rated power within the range of 120 W to 1000 kW are applicable. For this reason, the energy efficiency of most low-voltage high-power motors meets the requirements of this standard. In recent years, the proportion of low-voltage high-power motors that have passed the first-level energy efficiency (IE5) and second-level energy efficiency (IE4) certifications has continued to increase, which meets the needs of industrial energy-saving transformation under the “dual carbon” goal and has gained more market recognition.
Q5 What are the main applications of low-voltage high-power motors?
Low-voltage high-power motors are widely used in high-energy consumption fields such as steel, petroleum and petrochemicals, cement, mining, electricity, water conservancy, and textile machinery due to their high energy efficiency, energy saving and emission reduction, stable operation, strong reliability, simple maintenance, and low cost. These fields have harsh operating environments, high operating intensity, high speed regulation accuracy, and higher requirements for motors. Low-voltage high-power motors have gained favor from more industries with high reliability, simple maintenance, and lower costs. For different types of low-voltage high-power motors, their application scenarios are slightly different:
1. Low-voltage high-power industrial frequency motors are mainly used in lifting equipment and conveying equipment in the mining field, rolling equipment in the metallurgical field, etc., because they can tolerate high inertia loads and frequent start-stop, meeting the needs of high-intensity continuous operation.
2. Low-voltage, high-power variable-frequency motors are mainly used in situations where variable-frequency speed regulation is required. Because they support wide-band speed regulation, they are mainly used in industrial compressors, large industrial water pumps, blowers in sewage treatment systems, etc. At the same time, variable-frequency motors have the advantages of fast dynamic response, high speed regulation accuracy, large overload capacity, high mechanical strength, complete protection functions, high reliability, and easy operation. They are also popular in industries such as steel, metallurgy, mining, petroleum, textiles, machinery, and electricity, and have significant social and economic benefits.
The low-voltage, high-power industrial frequency motors produced by Qingdao Enneng Motor Co., Ltd. have the advantages of beautiful appearance, compact structure, light weight, high efficiency, energy saving, low noise, low vibration, high reliability, long service life, and easy installation and maintenance. They are widely used in the field of petrochemicals. Low-voltage, high-power variable-frequency speed-regulating motors are mainly used to drive steel mill rolling mills, curling machines, leveling machines, shearing machines, fans, water pumps, and other equipment. In recent years, with the increasing number of steel plant transformation or localization projects, the demand for replacing imported low-voltage high-power variable frequency speed regulating motors, such as Siemens and ABB, has also increased, and the order volume has shown an increasing trend year by year.
In summary, the proportion of low-voltage high-power motors in my country’s medium and large power motors has increased year by year, with rapid development and wide application, and its attention has also increased rapidly; at the same time, the country’s support and subsidies for high-efficiency motors have also promoted the further development of low-voltage high-power motors; in the future, low-voltage high-power motors will play a more important role in my country’s industrial development and contribute to my country’s high-quality development through continuous technological iterations and improving motor energy efficiency, in line with the country’s “dual carbon” strategic goals.
