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if the motor is burned out, but the inverter is still running. Why?

Date:2023-11-06   Author:XINDA MOTOR
If the motor burns out, why is the inverter still running?
★Although the frequency converter has soft start, soft stop, stepless speed regulation and special requirements of increase and decrease characteristics, it also has overload, overvoltage, undervoltage, short circuit, grounding and other protection functions as well as various early warning, forecast information and status information. and diagnostic functions; but if the power matching between the inverter and the motor is not selected correctly, or the basic parameter selection is not set correctly, the motor will burn out, but the inverter still has output; this situation generally does not occur when you are familiar with the inverter. in the work of the old masters.
Simply put, correctly setting the parameters of the inverter and motor, such as rated power, rated frequency, rated voltage, rated current, rated output capacity, etc., is the prerequisite to ensure the normal operation of the inverter and to give full play to the performance of the inverter and motor. Mastering the basic parameter setting method is the key to operating the inverter.
No matter what brand of inverter and motor, if the power matching is consistent, the motor parameters must be self-study (also commonly known as automatic tuning). It is an accurate copy of the parameters on the motor nameplate of the inverter mopping the floor. To the memory chip inside the inverter; copying the motor parameters to the inside of the inverter includes two steps: parameter upload and parameter download. Parameter upload refers to uploading the parameters in the inverter control panel to the memory (EEPROM) of the operation display panel. Save; parameter download refers to downloading the parameters stored in the operation display panel to the control panel of the inverter and saving them.

In this way, once there is a problem with the motor, the detection sensor inside the inverter will analyze it through the processor and make a judgment. When a certain standard is reached, the inverter will execute immediately and stop the U, V, W output voltage of the inverter, and the motor will be protected.
★Rated parameters of the frequency converter. (1) Rated parameters of the entry side. ① Rated voltage → The rated voltage of low-voltage inverters includes single-phase 220~240V (mainly small-capacity inverters in household appliances), three-phase 220V or 380~460V. The rated voltage of my country's low-voltage inverters is mostly three-phase 380V, and the rated voltages of medium and high-voltage inverters are 3kV, 6kV and 10kV.
②Rated frequency → Generally stipulated as power frequency 50Hz or 60Hz, in my country it is 50Hz. (2) Rated parameters of the output side. ① Rated output voltage → Since the output voltage of the inverter changes with frequency, its rated output voltage can only be specified as the maximum value of the output voltage, which is usually always equal to the rated voltage of the input side.
② Rated output current → Rated output current refers to the maximum current allowed to be output for a long time, and is the main basis for users to select an inverter. ③Rated output capacity→The rated output capacity is determined by the product of the rated output voltage and the rated output current:. Se=√3UeIex10?3. S in the formula... rated output, kVA; Ue... rated output voltage, V; Ic... rated output current, A. It should be noted that the rated capacity of the frequency converter is expressed in terms of rated output current (A), rated active power (kw), and rated apparent power (kVA).

④ Equipped motor capacity → The equipped motor capacity specified in the inverter manual refers to the maximum motor capacity that can be equipped when driving a continuous and constant load. When the rated capacity of the frequency converter is expressed in terms of rated apparent power, the apparent power required by the motor should be smaller than the apparent power that the frequency converter can provide. The specific size can be determined by referring to the above requirements. When using a frequency converter, the apparent power of the motor is calculated as follows:
S=P?/η.cosφ In the formula, S-...the apparent power of the motor, kVA; P?...the rated power of the motor, kW; cosφ...the power factor of the motor. This value is smaller than the industrial value due to the influence of high-order harmonics. The power factor under high frequency voltage is smaller and can be corrected according to the performance of various frequency converters;
η...Motor efficiency, as mentioned above, is also smaller than the value at power frequency voltage. ⑤ Overload capacity → The overload capacity of the frequency converter refers to the ability to allow its output current to exceed the rated current, which is generally specified as 150%le, Imin or 120%le, Imin.
⑥Output frequency range → The maximum adjustment range of the output frequency, usually represented by the maximum output frequency fmax and the minimum output frequency fmin. The frequency range of various frequency converters is different, usually the maximum output frequency is 200~500Hz, and the minimum output frequency is 0.1~1Hz.
⑦ Starting torque at 0.5Hz → This is an important characteristic index of the inverter; an excellent inverter can output a high starting torque of 180% to 200% at 0.5Hz. This kind of frequency converter can realize smooth acceleration and deceleration in a short time according to the load requirements, and quickly respond to sudden load changes.