OSC482L powerful software function, can be used to measure and analyze the counter electromotive force of the permanent magnet motor output, forms the basic wiring are:
The oscilloscope pens and pick up A phase winding motor output, A ground wire C phase winding, pens and electronic phase winding B, B
, under normal circumstances, if we turn the motor in the three-phase winding of the motor will generate induced electromotive force, and the induced electromotive force by sine wave, the oscilloscope can detect,
The induced electromotive force on the permanent magnet synchronous motor winding with the increase of rotational speed output voltage will be bigger, oscilloscope display screen can be seen from above, the voltage from zero gradually increases to a certain value to maintain,
Can be measured by such images, have to say, the LOTO superior software provided by the single adjustable threshold helped trigger function,
Single trigger function is only provided in A channel, as shown in the above, A page in A channel on the right side of the button, shown as A "trigger", one click, we can see above, check the "trigger" check box, we can open the trigger function, optional rise along the falling edge trigger and trigger two trigger mode, you can use the "conventional trigger" and "single trigger,"
After open "rising along a single trigger", as long as we appropriately adjust the trigger level, can complete the above graphics collected,
LOTO software also not only that, can also access the waveform of the measurement and calculation,
Select the measurement button, on the waveform to draw a rectangle, you can see the selected rectangle frame corresponding to the time and amplitude of waveform
Also can undertake spectrum analysis on the current waveform, just click on "FFT Fourier transform", as shown in the figure below, you can see the Fourier analysis of the two groups of waveform, a peak at 0.137 KHz, we collected the induced emf waveform frequency of 0.137 KHz, cycle is about 7.299 ms,
Software also provides a special sense of tool, is to get the cycle of the waveform multi-point measurement,
Picture below shows A channel, and B channels of waveform of multi-point measurement results, you can also provide A channel, and B channels corresponding differential measurement point as A result,
Through a separate channel multi-point measurement results we can also calculate the wave cycle, for example, 0-1-2 for a cycle, we will be at 2 o 'clock time minus zero income difference basic is the cycle of the current waveform, 24.353-15.131=9.222 ms,
Due to A channel, and B channels waveform frequency is the same, according to A, B two channel corresponding to the time difference value of measurement point we can calculate A, B two channel waveforms of the initial phase difference value,
Channel measurement point from the waveform diagram you can see, A time of 19.815 ms, 1 B channel corresponding to the time of 18.217 ms, can know A, B, corresponding points difference of 19.815-18.217=1.598 ms,
We have measured the waveform in front of the cycle of 9.222 ms, you can calculate B channels are A channel for phase:
1.598/9.222 * 360=62
We analyze two analog signal can be measured, A, B, C are the same length, phase difference of 120 degrees, but the way we measure is A channel to measure A phase winding, winding channel measurements B B, C phase winding ground, so the actual measure oscilloscope is A - C and B - C phase line voltage analog,
Their mutual difference between 60 degrees, our actual measurement is 62 degrees, basically meet the theoretical calculation results,
Conclusion:
OSC482L provides variable threshold single trigger function, rich in waveform calculation and measurement functions, can meet the demand of practical application,