The inverter is an electric control equipment that uses frequency conversion technology and microelectronic technology to control and communicate the motor by changing the power supply frequency of the motor operation. The inverter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to communication), braking unit, drive unit, detection unit and microprocessor unit. After changing the frequency of the power supply to achieve the intention of changing the power supply voltage, according to the actual demand of the motor to supply the power supply voltage it needs, and then to achieve the intention of energy saving and speed regulation, in addition, the inverter has many maintenance functions, such as overcurrent, overvoltage, overload maintenance and so on.
What is the difference between overload and overheating of an inverter? The causes of overcurrent are as follows:
First, under normal circumstances, the current trips, and the inverter will show OC problems;
The second is that the inverter module is damaged, and at this time, it will show faults as soon as it is turned on, the module is bad, the output voltage is unbalanced, and the load current rises rapidly;
Third, the increase of load torque is blocked, or the acceleration and deceleration time is set improperly, and the torque changes abruptly, causing the current to rise;
Fourth, there is a mismatch between the motor capacity and the power of the inverter, generally the motor power is too large and the inverter is too small.
Overload maintenance, which is the maintenance measures adopted to prevent the power of the load from being too large; Overcurrent maintenance is a maintenance measure taken to prevent excessive current. Overload tripping sometimes also shows OC problems, sometimes OH problems, OH is overtemperature, inverter heat dissipation is poor, and OH will appear when the temperature rise of the module reaches a certain value. In personal experience, current tripping and overload tripping are the difference above.
The reason for the overcurrent exceeding the limit is that the motor is severely overloaded for a short time or other factors; The reason for the overload is that the overload will cause the temperature rise of the motor to exceed the standard.
The inverter is an electric control equipment that uses frequency conversion technology and microelectronic technology to control and communicate the motor by changing the power supply frequency of the motor operation. In order to maintain the safe operation of the equipment, the inverter will set current over-limit (over-current) maintenance and overload over-limit maintenance during operation. Proactively take appropriate measures such as alarms or shutdowns when the limit is exceeded.
Overcurrent means that the current of the motor (inverter output) exceeds the specified value; Overload is when the load of the motor exceeds the rated power of the motor. The main cause of overcurrent and overload is motor overload. The reason why it is divided into two objectives is as follows:
1. The goals of maintenance are different between the two. The overcurrent is mainly used to maintain the inverter, while the overload is mainly used to maintain the expansion of the motor. Because the capacity of the inverter is generally larger than the capacity of the motor. In this case, when the motor is overloaded, the inverter does not have to be overcurrent.
2. The rate of change of the current is different. Overload maintenance occurs during the operation of the production machinery, and the change rate of the current is generally small: other overcurrents other than overload are often sudden, and the change rate of the current is often large.
3. The method of maintenance is different. Overload maintenance has an anti-time characteristic. Overload maintenance is mainly to prevent the motor from overheating, so it has the "reverse time limit" characteristics similar to that of thermal relays. In other words, if you do not exceed the rated current much, you can agree to operate for a longer time, but if you exceed it more, the time for promised operation will be shortened. In addition, because when the frequency drops, the heat dissipation of the motor becomes poor.
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