Comment summary #31
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Comment 301 ... 310
| date | article | author | comment |
| 19 feb 2016 11:34:54 | Arduino wattmeter | Freddy | Are you sure you didn't alter the program? And are the calibration values both positive? |
| 19 feb 2016 11:31:33 | Current transformers | Freddy | The turn ratio is 1:50. The primary impedance is calculated by Vp RMS /Ip RMS . Because this thansformer was so small, a function generator was sufficient to deliver the current. If you're measuring on larger transformers you have to boost the output power. A audio amplifier with a series resistance of 4...8 Ω will do. |
| 19 feb 2016 10:53:18 | Current transformers | Dennis | Hi, great article! I am interested in how you obtained figure 8, what measurement setup did you use? I have tried to do the same measurement, but my signal generator can not handle the transformer. I am measuring a 100W CT rated for 6.6A. (one of these: http://www.efla.net/products/agl-transformers-for-series-circuits/) and why the primary impedance is so low? you are using an Rs of 8.3 & 50 ohms, what is the turn ratio of the CT? |
| 19 feb 2016 08:26:56 | Arduino wattmeter | angel | It now reads from A0-2. Thanks. I encountered a problem with the Real Power, the display on the LCD is negative. When I checked the voltage and current, they are both positive when displayed on the LCD. |
| 18 feb 2016 19:30:51 | Arduino wattmeter | Wolfram Fischer | Hi Peter, i think it should be working at nearly any current, you just have to put in the right shunt-resistor! for 630Amps it would be a fat one, maybe a piece of copper with 7,8571428571428571428571428571429e-5 Ohms :-) |
| 18 feb 2016 17:27:55 | Arduino wattmeter | peter | Dear Freddy , I was wondering, can this system measure a system that has a voltage and a current at, 1-5 V and 630 amps ? I'm currently trying to continously measure the power input to a switchgear. We have the equipment for spot measuremets but not continous. I'm wondering, can your system handel the 630 current ? Best regards Peter |
| 18 feb 2016 11:09:22 | Arduino wattmeter | Freddy | There is no variable for reverse current. Use the mean value and check if it becomes negative. |
| 18 feb 2016 05:49:09 | Current transformers | Chari | Very good post on CTs, I also have an article regarding types of CTs on my page if anyone is interested in learning more about Current Transformer Theory: http://electricalsmarts.com/current-transformer-theory/ |
| 17 feb 2016 06:53:08 | Arduino wattmeter | Wolfram Fischer | Where can i find a variable for reverse (-) current? I want to change the lcd background colour if current is reversed. (Using a 2x16 with RGB Backlight) |
| 16 feb 2016 23:49:28 | Arduino wattmeter | Wolfram Fischer | ok, i will get it a try for both things, HI/LO Range and 2nd LCD. Thanx for your great Projekt! |