【Daily Question 20090306】Parameter setting of inverters?

It’s probably used for the overload protection safety settings

This is provided to enable the inverter to offer overload protection for the motor. Generally, when a motor is not driven by an inverter, overload protection can be achieved using thermal relays or motor protectors; however, motors driven by inverters have an additional method of protection, namely the electronic thermal protection function built into the inverter, which relies on the rated current of the motor under normal operating conditions as a basis for making decisions. Here is a brief introduction to the current of inverters: The input current of an inverter is lower than the output current when the operating frequency is below the mains frequency, as in such cases the output voltage is lower than the input voltage. At an operating frequency of 50 Hz, the input current is greater than the output current of the motor when it is not driven by frequency conversion, because the input current contains higher harmonics, while only the fundamental component does the actual work.

Regarding modeling, when using an inverter to control a motor, it is necessary to model the controlled motor within the inverter. In other words, by accurately entering the motor nameplate data, a calculation of the motor model is performed. Power it on again to perform cold-state motor identification. Typical imported frequency converters have these functions. It is crucial for subsequent practical use to ensure that this work was done carefully and correctly. Taking Siemens inverters as an example (I use Siemens products, hehehe), there are specific procedures for calculating motor parameters and identifying the motor in a cold state, known as \"Quick Debugging\". After connecting the motor to the inverter for the first time, it is necessary to carry out a \"quick adjustment\". However, I have found that some users mistakenly believe that with V/F control, there is no need to perform cold-state identification of the motor; static calculations alone are sufficient. What is not realized is that even for the simplest V/F control, a motor model is required. Cold-state identification involves measuring the resistance and inductance values of the motor windings while the power is off. It is a basic parameter for modeling. Does Schneider’s need to be the same as well? If the motor model is not properly established, control will naturally suffer from deviations.

1. Overcurrent protection is the most important and fundamental protection function for the load, and it must be configured correctly and reliably. 2. The function group parameter (FUN49) is used to set the output current of the inverter to a level that continuously exceeds the current protection limit (i.e., a percentage of the inverter’s rated current). 3. The function group parameter (FUN50) is used to set the overcurrent duration. 4. Generally, the overcurrent setting is 110% for a duration of 60 seconds. 5. When the inverter is in operation, if the motor generates noise or interferes with other control devices in the same control cabinet, the user can adjust the carrier frequency within a certain range to reduce the noise or interference. :handshake

An inverter is generally a power control device that uses the on-off action of power semiconductor devices to convert mains electricity into electrical energy at another frequency.

The parameter settings must be tailored for the specific motor controlled by the inverter; the correct values specified on the motor’s nameplate must be used, as the default settings provided by the inverter manufacturer do not always correspond to the parameters of the motor being driven. Entering the correct rated current value of the motor also ensures that the inverter’s overload protection mechanism is properly activated.

I also think it represents an effective form of protection against overcurrent and overload conditions in motors. Our company uses the most Siemens frequency converters, so we are familiar with this aspect as well. It turns out there are many other reasons as well; thanks to those who posted above.