Regarding the starting of the motor
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In production, there is a centrifuge equipped with a motor that is a 7.5 KW two-stage motor; starting is done via variable frequency drive (under load), and recently the variable frequency drive burned out. I have a question: In cases where the load is not too high, can we use a motor with a higher power rating (such as 11 KW), so that there is no need for variable-frequency starting?
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Learning*, learning*. Looking forward to a reply from an expert
Is a three-speed motor used? Centrifuges generally require three speed settings, or at least two; removing the frequency converter entails modifying the cable tray, dealing with galvanized steel pipes, adding cables, and altering the cabinet, which is not worth it. And how did that inverter get damaged?
Let’s first find out the reason why the inverter is damaged! We can increase the power level of the inverter by one stage
The frequency converter generally needs to be one capacity level higher than the motor’s rated power
It can start automatically under no-load conditions; light loads allow star-delta or reduced-voltage starting
The damage to the inverter doesn’t seem to be closely related to the motor’s power. If the inverter is damaged, it’s necessary to check what caused the issue. If the motor is intact and the load isn’t heavy, it might be possible to start the motor directly at full voltage without using an inverter, thus avoiding the need to replace the motor with a larger one!
The motor is not large; if speed control is not required, it can be started directly.
The reason is whether the frequency converter you have chosen is a heavy-duty type In applications with heavy loads such as centrifuges and mixers, the power of the inverter needs to be one tier higher than that of the motor. When the inverter operates at low frequencies for an extended period, the torque is at its maximum, causing the inverter to become overloaded. Coupled with poor heat dissipation of the inverter within the control cabinet, it is inevitable that the inverter will get damaged.