UPS power test to pay attention to what the problem
?The efficiency of the UPS can be measured by measuring the UPS output power and input power. UPS efficiency is mainly determined by the inverter design. Most of the UPS only 50% -100% load only when the high efficiency, when less than 50% load, the efficiency of the sharp decline in the manufacturers to provide the efficiency indicators are mostly in the rated DC voltage, rated load conditions effectiveness. User selection is best to choose the efficiency and output power curve and DC voltage changes positive and negative 15% efficiency. Two dynamic test 1, sudden or sudden load test First, "power perturbation analyzer" measurement of no-load, steady-state phase voltage and frequency, and then sudden load from 0 to 100% or by reducing the load from 100% to 0, if the UPS output transient voltage between -8% to 10%, and within 20ms to return to steady state, then the UPS of the indicators qualified; if the UPS output transient voltage beyond this range, it will produce more Large inrush current, whether on the load or the UPS itself is extremely unfavorable, then the kind of UPS should not be used. 2, the conversion characteristics of the test This main test by the inverter power supply conversion to the mains power supply or by the utility power conversion to the inverter power supply conversion characteristics. Tests need to store oscilloscopes and regulators that can simulate changes in utility power.
The output voltage of the UPS can be tested by the following method:
A, when the input voltage is 90% of the rated voltage, and the output load is 100% or the input voltage is 110% of the rated voltage. When the output load is 0, the output voltage should be kept within the range of plus or minus 3% of the rated value The
B, when the input voltage for the rated voltage of 90% or 110%, the output voltage of one phase for the no-load, the other two for 100% load, the output voltage should be maintained at or minus 3% of the rated value, its The phase difference should be kept within 4 degrees.C, when the UPS inverter input DC voltage changes positive and negative 15%, the output load of 0-100% change, the output voltage should be maintained at or minus 3% of the rated voltage. This indicator on the surface with the previously described indicators repeat, but in fact it is higher than the previous requirements of the indicators. This is because the control system of the input signal changes in a wide range, showing a significant non-linear characteristics, to make the output voltage does not exceed the allowable range, the circuit requirements are even higher. effectiveness
?The frequency of the output voltage can be observed with an oscilloscope and measured with a "power perturbation analyzer". UPS current output voltage frequency is generally able to meet the requirements. But when the UPS frequency circuit, the local oscillator is not accurate enough, it is possible in the mains frequency instability, UPS output voltage frequency also followed changes. UPS output frequency accuracy is generally synchronized with the mains, can achieve positive and negative 0.2%. The output voltage
A steady-state test The so-called steady-state test is the device into the "normal system" state of the test, the general measurable waveform, frequency and voltage. Waveform
????Usually in the no-load and full load state, the observation waveform is normal, with the distortion measuring instrument, measuring the output voltage waveform distortion. Under normal operating conditions, then the resistance load, with the distortion measuring instrument to measure the output voltage of the total harmonic relative content, should meet the requirements of the product requirements, generally less than 5%. frequency
