Frequently Asked Questions about Drives and inverters
1. Why is the leakage circuit breaker tripping easily when using the inverter?
This is because the output waveform of the inverter contains higher harmonics, and the cable between the motor and the inverter and the motor generates leakage current. This leakage current is much larger than that of the power frequency drive motor, so this phenomenon occurs.
The leakage current on the output side of the inverter is about three times that of the power frequency operation. In addition to the leakage current of the motor, the operating current of the selected leakage protector should be greater than 10 times of the leakage current at the power frequency.
2. I want to do the motor frequency conversion speed regulation experiment. Can ordinary motor realize the frequency conversion speed regulation? Still have to buy a variable frequency motor?
It is enough to use an ordinary AC motor for the motor frequency conversion speed regulation experiment.
The DC motor can also realize frequency conversion. For example, the current DC inverter air conditioner: it converts the power frequency AC power into a DC power supply and sends it to the power module. The module is controlled by the control signal sent by the microcomputer, and the AC output frequency is different from the module output. The controlled DC power is sent to the DC motor of the compressor to control the displacement of the compressor, thereby achieving “frequency control”.
3. What kind of motor is an AC variable frequency motor?
Simply put, the inverter technology is used in the control of the AC motor. The AC variable frequency motor is actually a kind of motor that adjusts the frequency of the alternating current to adjust the frequency of the alternating current. The frequency of the alternating current depends on the frequency converter. The motor itself does not convert the frequency. In many occasions where the requirements are not high, the ordinary motor plus the frequency converter is used to regulate the exchange. Inverter motor use.
4. What is going on after the motor is added to the inverter?
The sound of the “weng” is caused by the carrier frequency of the inverter output waveform. Usually, if the inverter you are using is a fixed carrier, then the motor emits a scream, which is more irritating to the human ear. You can adjust the carrier frequency (this function parameter is available in the function manual of the inverter technical manual). The higher the carrier frequency, the smaller the sound, but the higher the carrier, the more likely the motor will heat up. Therefore, we should consider the carrier frequency you use according to the heating program and the sound emitted. Generally, it is the most suitable carrier frequency at the rated current when leaving the factory. Under normal circumstances, you do not need to change it!
If the inverter uses a random carrier, the “weng” sound from the motor will be softer, but the sound will generally be better than the sound of a fixed carrier. Hehe (more acceptable), if you don’t accept it, or if you want to mute, you can also adjust the carrier frequency up to the satisfaction.
5, the inverter single phase 220v can change the three-phase 380v?
The inverter itself cannot be boosted, and it is impossible to change the three-phase 380v from the single-phase 220v. But in theory this is feasible, using a transformer to raise the single-phase 220V to 380V, and then convert the single-phase 380V to three-phase 380V.
6, Emerson ev2000 37kw inverter shows how to deal with e018?
You can use a multimeter to measure whether the coil circuit of the contactor is normal, check whether the plug on the board is loose or poorly contacted, whether the small relay on the drive board is working properly, whether the contactor auxiliary contact is bad, you can wipe or replace the contactor.
7. Answer the reason why the motor speed is slow when starting the motor?
If it is only slow at start, it will be normal after starting. It may be that the starting capacitor does not match, or the motor design is originally such (according to the design of the place), or it may be that the starting time is too long due to factors such as excessive load resistance.
If the speed is slow after starting, the problem may be insufficient voltage, mismatched capacitance, and high rotational resistance.