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| How can one measure the speed of a 3-phase generator electrically? |
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| shamooooot:
Unfortunately it didn't work.. I tried with couple of frequency counters and they didn't pick the phase to phase frequency, which I think is due to the low AC voltage (0-12V).. I stepped up the voltage 30 times using a transformer but they again struggled to detect the frequency, they get stuck at a value and never recover until I turn them off and on again.. I can't use any kind of sensors or modifications due to some limitations I have.. The generator is Three-phase AC permanent magnet synchronous generator. Any ideas for a reliable circuit that I can use? I have a USB-6009 device. |
| soldar:
Vaguely defined questions get generic answers which may help someone who is knowledgeable enough. If you want more detailed help I would suggest you spend some effort in specifying the question in much greater detail. This is an extremely simple problem for someone with basic knowledge. Is this work-related? Because you seem to be out of your depth. |
| Jeroen3:
For a <1 kHz generator, 48 kS/s is more then enough to extract the zero crossings from an analog input by software using interpolation. The algorithm is very simple. Find the two pairs of samples where the sign changes. Use the buffers sample numbers and store them. Interpolate the exact position of the crossing as percentage of the time between samples, store it. Convert the stored numbers to a sample count difference, and then to time using the samplerate and the interpolated percentage. Use the time between two interpolated crossings to determine the frequency. You may need to average the output for additional resolution. Accuracy depends on the samplerate and it's jitter. I have no clue how you do this with a NI DAQ, but if it can output a stable stream of samples this should be trivial in any programming language. |
| EPAIII:
Some DMMs (Digital Multi Meters) have both a frequency function and the ability to send an output to a computer, usually via a USB port. The advantage of using such a meter would be that it is already set up to accept different input Voltage levels. https://www.google.com/search?q=DMM+with+frequency+scale+and+USB+output&client=firefox-b-1-d&sca_esv=568147601&sxsrf=AM9HkKlUxkl8yKY52V00sJnvWyihrw4j5A%3A1695637124472&ei=hF4RZbq5HOGrqtsPqN2Z0Ao&ved=0ahUKEwi6i-PDxMWBAxXhlWoFHahuBqoQ4dUDCA8&oq=DMM+with+frequency+scale+and+USB+output&gs_lp=Egxnd3Mtd2l6LXNlcnAiJ0RNTSB3aXRoIGZyZXF1ZW5jeSBzY2FsZSBhbmQgVVNCIG91dHB1dDIFECEYoAEyBRAhGKABSJo8UP8MWNEccAF4AJABAJgBjAqgAfYkqgEHNS0yLjAuM7gBDMgBAPgBAcICCxAAGIoFGIYDGLADwgIFECEYqwLiAwQYASBBiAYBkAYD&sclient=gws-wiz-serp |
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