Wind Generator Wattage monitoring
Posted 22 December 2008 - 03:15 PM
Posted 23 December 2008 - 07:49 AM
Posted 24 December 2008 - 03:22 AM
Posted 26 December 2008 - 09:25 AM
That clamp-on probe just outputs a DC voltage related to the RMS current, so is very easy to use.
Here is a topic about inexpensive current monitoring:
Here is some related information from a support email:
Ohiosemitronics.com has various transducers. The AVT-150 series
(0-150 single phase AC input) is $98 for 0-5 or 0-10 VDC output. The
AVTR series adds true RMS and starts at $258:
Yokogawa has AC voltage or current transducers for $75:
Only useful output option is 4-20 mA, so connecting to the LabJack
will require a resistor or LJTick-CurrentShunt. See current
measurement in the analog input section of user's guide.
Posted 04 January 2009 - 10:13 PM
The hall effect sensors eliminate the need for a current shunt since an insulated wire can be passed through the bead without wiring the mains anywhere near your Labjack. They work like the current clamp meter noted above except if it is going to be used permanently then using a hall-effect sensor can allow you to recover your expensive clamp meter! The sensor output (5V, 0V and sensor output pin) can be simply adapted to the Labjack analogue inputs (the HV inputs are probably the simplest to connect without external op-amp, but you could use an op-amp and null-offset adjustment to adapt to the LV analogue inputs just as easy if you are ok with an op-amp circuit). Hall effect sensors like these may also be used for DC currents as easily as AC currents. These sensors can be readily applied to a whole lot of Labjack projects where current sensing is required. If you want to thread a few of them on the same wire, then you can have component redundancy and use the average value from two or three. If you have already bought a clamp on current meter then that could help you to calibrate your current measurements via the Labjack.
Examples of excellent low-cost mail-order hall-effect sensors for current measurement can be found at; http://www.raztec.co.nz/Products.html
The typical cost is around USD3.5 per unit (might vary by a few cents depending on model, qty and shipping dest) and the guys there are friendly, helpful and can ship within a few days.
You may also wish to excercise extreme care with mains voltages - even when you generator is stationary if the generator output remains connected to your distribution board then naturally it could kill you (or your buddy, or his mate) faster than blinking.
I hope this helps.
Posted 16 January 2009 - 12:45 AM
Posted 18 January 2009 - 02:30 AM
Posted 19 January 2009 - 03:57 PM
Posted 30 January 2009 - 11:26 AM
One suggestion would be to pick a sensor that runs off 5 volts, which you can get from the U3. Topic 4274 mentions the Tamura L01Z series.
You mean 10A RMS? Thus you have a current sine going from about -14 to +14 amps. If you are powering the sensor from 9 volts, your output signal would be a sine wave with a max of about 5 volts and a min of about 4 volts. How do you connect this to the U3, how do you collect the waveform (stream mode?), and what math do you do in software (RMS calc?)?
Hi guys, I ordered the LO1Z by Tamura. I hooked it up but did not put the 10k resistor onto the signal line. Hoping it would work without it. I tested using the same methods as before and got the same wacky results. It would work at first, then I would stop current flow and restart. Then, it would show a negative current flow. And each test would produce different results. Is it because of the missing resistor. And I'm not using stream mode. I'm just collecting the voltage from the sensor as an input. I use a formula in the conversion area to produce a graph that should represent approximate current. Any thoughts on why my results are so wacky.. Thanks guys, your the best.
Posted 30 January 2009 - 08:40 PM
Posted 31 January 2009 - 05:17 AM
Posted 02 February 2009 - 05:02 PM
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