I. How to wire a power filter
A power filter is a filter circuit composed of capacitors, inductors, and resistors. It is also known as a "power EMI filter" or "EMI power filter". It is a passive bidirectional network with a power supply at one end and a load at the other end.
Do not bundle the power supply and load wires of the filter together, as this will increase the electromagnetic coupling between the filter's input and output terminals and weaken its ability to suppress EMI signals.
To avoid the input and output lines of the power filter being too close together, they must be spaced out and never run in parallel, as this will reduce the filter's efficiency.
To avoid using long grounding wires, the wiring length connecting the output of the power filter to the frequency converter or motor should not exceed 30 cm.
Shielded twisted-pair cables are preferred for the input and output connections of the power filter, as they can effectively eliminate some high-frequency interference signals.
The power filter housing must make good contact with the chassis housing, and the grounding wire must be connected.
The LOAD terminal is connected to the load, meaning N is connected to the neutral wire, L is connected to the live wire, and the three E's on the right are grounded. N is connected to the neutral wire, and L is connected to the live wire. This is the power input terminal.
The connection method is as follows: connect input L to 1 and N to 2; connect output L' to 3 and N' to 4; and ground the wire to ground.
II. How to evaluate the performance of a power supply filter
A common method for evaluating the performance of power supply filters is to use a spectrum analyzer. A spectrum analyzer can perform spectral analysis on the signal output from the power supply filter, obtaining the signal's spectrum. By observing the spectrum, we can determine the filter's suppression of noise and interference at different frequencies. If the filter effectively suppresses high-frequency noise and interference, the spectrum should show low amplitude in the high-frequency range. Furthermore, by comparing the spectrums of different filters, a filter with better performance can be selected.
Another way to evaluate the performance of a power supply filter is to measure its transfer function. The transfer function refers to the amplitude and phase relationship between the filter's input and output at different frequencies. By measuring the transfer function, we can understand the filter's gain and phase characteristics. A good filter should have the flattest possible gain and linear phase characteristics. The transfer function can be measured using a signal generator and an oscilloscope.
Another factor to consider when evaluating the performance of a power supply filter is its noise suppression capability. Noise suppression capability refers to the degree to which a filter suppresses noise and interference in the input signal. This can be achieved by introducing noise and interference of different frequencies into the input signal and then observing the amplitude of the filter's output signal. A good filter should be able to effectively suppress noise and interference, resulting in the lowest possible amplitude of the output signal.
The filter's error and distortion also need to be considered. Error and distortion refer to the difference between the filter's output signal and the input signal. The filter's error and distortion can be evaluated by measuring the difference between the input and output signals. A good filter should have low error and distortion to ensure the accuracy and stability of the output signal.
