Seeking help with issues regarding variable-frequency motors
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6kV motors require frequency conversion; is it necessary to use a motor with frequency conversion capability, and why? Can a regular motor be used if the frequency variation is within 20%? Are low-voltage motors the same? Thank you for the expert guidance.
Ordinary motors are designed based on the frequency of the mains power and the corresponding power level, and they can operate stably only under rated conditions. Variable-frequency motors are different; they have to overcome overheating and vibration at low frequencies. Therefore, they are designed to have better performance than ordinary motors. For example, variable-frequency motors are equipped with powerful cooling fans (powered by a separate power supply) to ensure proper cooling at low speeds.
It mainly depends on your load type. If it’s a fan or water pump load, there’s no need to use an inverter-driven motor! There are two main reasons: 1. The investment is too high; it’s not necessary ； 2. The speed regulation range for such loads is usually 100% to 70%, so ordinary high-voltage motors are fully suitable for these speed regulation requirements.
A frequency conversion range of 20% means operating between 40Hz and 50Hz, right? If it’s not a heavy-duty constant-torque device, ordinary motors should be sufficient for this range!