After the frequency converter increases the frequency to over 50HZ, remains the voltage at 380V?
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It is said that when the frequency exceeds 50Hz, both voltage and current change? Please give me some advice.
When the voltage is above 50Hz, the inverter operates in constant power mode; at this point, no matter how the frequency increases, the motor’s power remains unchanged, staying at its rated value. An increase in frequency means an increase in voltage, resulting in a decrease in current.
That can’t be right; then what’s the point of operating at over 50Hz?
Increase the pump’s head or flow rate~~
Above 50HZ, under constant power operation, the voltage increases, the current decreases, the speed increases, and the torque decreases. Depending on the process speed control, it can operate above 50HZ. For example, some mixing is necessary.
The advantage of operating above 50HZ is to achieve the speed required by the process; this operation mode is a constant-power mode, and in it if the power supplied to the motor increases proportionally, then the motor’s power increases in proportion to the frequency, leading to premature overload of the motor. To provide some additional information, the second operating mode of inverter-driven motors is the constant torque mode, in which the motor’s power increases in proportion to the frequency; the maximum speed control range is 50 HA, at which point the motor operates at its rated power.
Firstly, the operating voltage exceeds the power frequency value; the power remains unchanged while the torque decreases. We have also operated in both 10kv/0.4kv modes, and the voltage will not increase above 50HZ!
Can a pump’s head and flow rate be increased without raising its power?
I don’t fully understand the principle, but I have encountered cases where the fan’s output was insufficient; in such situations, the upper limit was increased to 55Hz, allowing the fan to operate at above 50Hz to meet the requirements.
For an inverter to operate at a frequency higher than the rated value, a constant power operation mode is required; this corresponds to the motor’s rated power, given by P=Tn/9550. As the frequency increases, the speed increases as well, but the torque decreases relatively. The head pressure of a pump is proportional to the square of its speed, while the flow rate is proportional to the speed itself. Therefore, it is not possible for both the head pressure and the flow rate to increase simultaneously – if one increases, the other must decrease