To answer this question, we must first understand the difference between the efficiency of a high-voltage motor and a low-voltage motor of the same power.
The fundamental difference between high-voltage and low-voltage motors is that the rated voltages of the two are quite different, which also leads to a large difference in the insulation structure of the stator winding between the two. However, from the comparison of the efficiency and performance of the whole machine, what is the relationship between the two? This is a question raised by a concerned motor practitioner. Today, we will communicate with you based on the national energy efficiency limit standards for high and low voltage cage motors.
GB18613 is the energy efficiency limit standard for low-voltage motors, and GB30254 is the energy efficiency limit standard for high-voltage cage motors. Both standards are mandatory standards.
Comparing the advantages of high-voltage motors and low-voltage motors, for high-power motors, due to the limitations of low-voltage motor manufacturing process and cost, high-power motors are more likely to choose high-voltage motors; motors with a power of about 200kW include low-voltage motors and high-voltage motors, but from Comparing the energy efficiency limit requirements of the two efficiencies, it is difficult to define which motor is more energy efficient.
Therefore, when selecting high-voltage and low-voltage motors, the limitations of conditions also naturally limit the degree of freedom of selection, but from the perspective of manufacturing, the development of high-efficiency motors is more conducive to the improvement of the overall energy-saving effect.
If the motor of the same power, the output power of the higher voltage is greater than the output power of the lower voltage, if the same 15KW motor, three-phase 380v and three-phase 220v voltage, then their power is the same
Since the power is the same, the power consumption will not be too much. Generally speaking, a high-voltage motor has a small current, and the coil generates less heat, so the power consumption may be relatively small. But not absolutely! If the coil wire of the low-voltage motor is thicker, the contact flux of the silicon steel sheet is higher, and the load and torque matching are better, the power consumption may be less than that of the high-voltage motor, because the power factor is higher, the current is lower, and the heat generation is lower. The key is that the ratio of electric power to shaft power is higher!
Unless the high-voltage motor of thousands of volts, the motor voltage is generally higher than the lower one, which is smaller, cheaper, and more efficient!
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Depends on the load.
If the load is the size of the single motor then that might be better, but if the load is half the full power rating often, then using one small one and bringing in the second as needed may be better.
So you need to understand the load.
A similar situation is often found for boilers where there is a leading and lagging boiler according to the demand. Usually they rotate every so often to even out the hours. One factory had six boilers and each was lead boiler for a week.