The way you are using that device will give you output pulses 2X the line frequency.
Paul
Most likely because the resistance value is kinda low. I'll work something out by tomorrow. Also, apreciate your help, guys.
No! Increase the R1 value so 380/R1 = 0.001 to 0.010 Amp!
Sorry, i mean lower the current, thus increasing the resistance. Kinda tired also.
Good work, well done! Not often such nice schematics are found here.
[ sorry, I got confused by the transform being a current transformer and posted nonsense ]
On reflection I see some confusion about using a current transformer.
A current transformer must be inline with the load, never never never ever across the mains!!!
A current transformer needs a suitable burden resistor or very bad things may happen (extreme voltages).
Its by far the best idea to get a current transformer with a built-in burden resistor so you don't have to worry about it - is this what you have (STC-013 by itself doesn't imply this (and its wrong, the part is SCT-013 anyway)). Burden resistors are low values, a current transformer is designed to work with the secondary shorted, never ever open.
The easiest way to use a CT with a built-in burden resistor is like the circuit in #6, but not connected across the mains as in that diagram - the secondary side is fine (you can lose the TVS diode and C1 and still be safe from overload as the 10k resistors limit the current into A1, C1 isn't doing anything useful)
You can't use 10k resistor as current limiter into A1. Current limiting is a not working idea. Make sure the volrage never exceeds 5 volt.
Huh? 10k is plenty for a few volts overload on an input protection diode. You could add a BAT74 as Schottky clamps if paranoid.
Being in an overload situation all values will be 1023. What's the point in that?
Havent being able to work at the project at all, will probably do it at weekends. But thanks for the feedbacks.
Okey. Come back with replies when You feel like.
Hi guys, my biggest problem is representing the STC-013 as a current transformer, since there is not current transformer in proteus, only the power ones. Does someone has a tip about it?
Also, i wanna share with you guys my first idea for arduino code. First, i think i can take about 166 samples per cycle (if the arduino clock is 10Khz, ignoring time delay, id be able to read the analog inputs every 0.1ms, since one cycle goes about 16,6ms, dividing one by another gets me to the 166 readings). Now, for the power consumption, id get all the samples of voltage and multiply them by current. My doubt is: is the arduino powerful enough to do that?
For the power factor, what i have in mind is locating the peak between those readings. For the current, i'd simply compare one peak to another, the diference between then would then give me the time delay between both, which i can use easily to calculate the phase shift between two currents. Now, the voltage one. I have decided also to calculte it using the same principle, since it does not matter the position that we put it in cartesian map, what matters is the difference between time delay (given by cosΦ).
Correct me if i am wrong, would this really work? Or its too much for the arduino to process at the same moment.
Since you are not doing this in real time, does it matter?
Paul
Of course, whenever the prototype is ready, it has to read and display those values in real time.
For the moment, im seeing what i can do with what i have, both on my mind and physical. For the moment, i have an arduino mega 2560, the sensors are coming up next week.
If you insist on finding a "peak", then by definition, you ONLY know a peak when a subsequent measurement shows the previous measurement was the peak. Not real-time.
On the other hand, zero crossing will tell you that this sample is at zero and that is real-time.
Paul
Yes, id know it hit a peak when the next value is lesser, but because of the sampling, it might screw up. I might add a voltage comparator to output high whenever one current is on the negative cycle of the AC. My biggest doubt its regarding current reading. By what i know, 220 AC transformers star connected shows no shift in current, but phase shift between two voltagens, whereas delta transformers shows the shift on voltage side.
Are we dealing with 3-phase power? IF the load on each is resistive, there will be no phase shift between the transformers.
Please show a schematic of what you are doing.
Paul
Well, thats some of its functions, monitor power factor. So, we must assume that not all loads connected are resistive.
Such devices have been used since the 1970's. Why are you trying to invent new one?
Paul
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.