Programmable AC power supplies can meet a variety of testing requirements, such as electrical EMC testing, third party quality inspection testing, low voltage electrical testing, film capacitor testing, etc. It is a test instrument commonly used in testing laboratories. With the application of programmable AC power, more and more people pay attention to the performance and common faults of programmable AC power.

 

500kW load bank
 

For example, when a programmable AC power supply has transformer magnetic saturation, the magnetic flux of the transformer will be reset through the positive series peak. However, due to a power failure, the magnetic flux does not reset, thus creating a state of residual magnetic flux on the negative side. Therefore, when the next positive string peak on the negative side reaches, the magnetic flux becomes more negative, exceeding the saturation flux density, and the inductance of the final excitation basically becomes zero. As the inductance disappears, the current and voltage fluctuate. This is because the current limit protection (OCP) of AC power supplies sometimes imposes current limits and sometimes does not, so there are fluctuations.

In order to prevent the programmable AC power supply from forming a short-time interrupt condition of overcurrent, even if the programmable AC power supply does not form a voltage current waveform under the short-time interrupt condition of overcurrent. We can take the case of a programmable AC power supply with a brief interruption of 10ms at a 90 degree phase Angle of 50Hz.

The magnetic flux on the positive side is the same as that on the negative side, and the magnetic flux will be reset (cancel each other out). As mentioned above, when comparing the positive side voltage waveform to the negative side voltage waveform over a period, no overcurrent is generated. When setting performance standards including power transformer product class 0.5, special attention is recommended to the impact of incoming current. In these products, the overcurrent may reach 10 to 40 times the rated current due to the saturation magnetic energy of the transformer core after the voltage plunge.

In addition, if overload problems cannot be avoided, the best approach is to increase the rated capacity of the AC power supply. This problem can be solved by running the model in parallel to supplement the insufficient capacity. For example, the 2000VA and 4000VA models are connected in parallel to serve as 6000VA AC power supplies. In this case, it is necessary to ensure that both models have the same firmware version.