Overload is one of the more frequent trips of the frequency converter . Overload faults include inverter overload and motor overload, which may be caused by short acceleration times, excessive DC braking, low grid voltage, and heavy loads. It can be solved by extending the acceleration time, extending the start-up time, checking the grid voltage, etc. Usually see the overload phenomenon, in fact, should first analyze whether the motor overload or the inverter itself is overloaded. In general, due to the strong overload capability of the motor, as long as the motor parameters of the frequency converter parameter table are set properly, overload does not generally occur. The inverter itself is prone to overload alarms due to poor overload capability. We can detect faulty points such as inverter output voltage and current detection circuit to eliminate faults one by one.
Overload troubleshooting methods (1) to check whether the motor heat <br> <br> If the temperature rise of the motor is not high, you should first check the inverter electronic thermal protection function preset was reasonable, as the amount of the inverter Shang Youyu , The preset value should be relaxed; if the allowable current of the inverter has no headroom, it can no longer be relaxed. According to the production process, the overload occurred is a normal overload, which means that the inverter is improperly selected, and the frequency converter should be increased. Capacity, replace the inverter. This is because, when the motor is dragging a variable load or intermittent load, as long as the temperature rise does not exceed the rated value, it is allowed to overload for a short time (a few minutes or dozens of minutes), and the inverter does not allow it. If the temperature rise of the motor is too high and the overload that occurs is a normal overload, it means that the motor is overloaded. At this time, first consider whether the transmission ratio can be increased properly to reduce the load on the motor shaft. If you can increase, then increase the transmission ratio; if the transmission ratio can not be increased, you should increase the motor capacity.
(2) detecting the motor phase voltage side is balanced three-phase voltage of the motor if <br> <br> side imbalance should then check the three-phase voltage inverter is balanced output terminal, such as uneven, the problem in the frequency Inside the device, check the inverter's inverter module and its drive circuit.
If the voltage at the output of the inverter is balanced, the problem is on the line from the inverter to the motor. Check that all the terminal screws are tightened. If there are contactors or other electrical appliances between the inverter and the motor, check whether the terminals of the electrical appliances are tightened and the contact status of the contacts is good.
If the motor side three-phase voltage balance, you should understand the operating frequency of the trip: If the operating frequency is low, and no vector control (or no vector control), first reduce the U / F ratio; if you can still drive the load , the original preset U / F ratio is too high, the excitation current peak is too large, can reduce the current by reducing the U / F ratio; if you reduce with a fixed load, you should consider increasing the frequency converter The capacity; if the inverter has vector control function, vector control method should be adopted.
(3) Check for malfunction
When no reason is found after the above checks, it is checked whether it is a malfunction. The method of judgement is to measure the output current of the inverter with a current meter under light load or no-load conditions, and compare it with the running current value displayed on the display. If the display shows a current reading larger than the actually measured current, More than one, it indicates that the current measurement part of the inverter has a large error, and the “overload†trip may be a malfunction.
Overload troubleshooting methods (1) to check whether the motor heat <br> <br> If the temperature rise of the motor is not high, you should first check the inverter electronic thermal protection function preset was reasonable, as the amount of the inverter Shang Youyu , The preset value should be relaxed; if the allowable current of the inverter has no headroom, it can no longer be relaxed. According to the production process, the overload occurred is a normal overload, which means that the inverter is improperly selected, and the frequency converter should be increased. Capacity, replace the inverter. This is because, when the motor is dragging a variable load or intermittent load, as long as the temperature rise does not exceed the rated value, it is allowed to overload for a short time (a few minutes or dozens of minutes), and the inverter does not allow it. If the temperature rise of the motor is too high and the overload that occurs is a normal overload, it means that the motor is overloaded. At this time, first consider whether the transmission ratio can be increased properly to reduce the load on the motor shaft. If you can increase, then increase the transmission ratio; if the transmission ratio can not be increased, you should increase the motor capacity.
(2) detecting the motor phase voltage side is balanced three-phase voltage of the motor if <br> <br> side imbalance should then check the three-phase voltage inverter is balanced output terminal, such as uneven, the problem in the frequency Inside the device, check the inverter's inverter module and its drive circuit.
If the voltage at the output of the inverter is balanced, the problem is on the line from the inverter to the motor. Check that all the terminal screws are tightened. If there are contactors or other electrical appliances between the inverter and the motor, check whether the terminals of the electrical appliances are tightened and the contact status of the contacts is good.
If the motor side three-phase voltage balance, you should understand the operating frequency of the trip: If the operating frequency is low, and no vector control (or no vector control), first reduce the U / F ratio; if you can still drive the load , the original preset U / F ratio is too high, the excitation current peak is too large, can reduce the current by reducing the U / F ratio; if you reduce with a fixed load, you should consider increasing the frequency converter The capacity; if the inverter has vector control function, vector control method should be adopted.
(3) Check for malfunction
When no reason is found after the above checks, it is checked whether it is a malfunction. The method of judgement is to measure the output current of the inverter with a current meter under light load or no-load conditions, and compare it with the running current value displayed on the display. If the display shows a current reading larger than the actually measured current, More than one, it indicates that the current measurement part of the inverter has a large error, and the “overload†trip may be a malfunction.
Elevator Switch Or Sensor,Host To Host,Host Brake Switch,Elevator Microswitch
Suzhou FUJI Precision Elevator Co.,Ltd , https://www.profuji.com