Dutch electricity meter reading

Post by **Bastiaan** » Sat May 16, 2009 10:10 pm

I got a transparent 3 phase energy meter with two rotating disks. The top one goes slow, the lower one runs faster and has red marks on it.
Does anybody know if the lower disk represents the power usage too?

I got RFXmeter picking up the disk now

but not sure if it is of any use.

Bastiaan

Post by **Bwired** » Sat May 16, 2009 11:00 pm

I think it is, is there any information on the meter somewhere?

Post by **Bastiaan** » Sat May 16, 2009 11:21 pm

It doesn't say much on the meter but it is an AEG 3x 10 amp(40) type no seems to be: C114G but not very clear.

Post by **Bwired** » Sat May 16, 2009 11:33 pm

If you can't find it on the internet, put a heavy device on, count the rotations and check/compare with the digits.
Its a dirty job but......

Post by **Bastiaan** » Sun May 17, 2009 9:51 am

Nothing on the internet yet but counting is hardly an option, it spins to quick.
So I will have to do a calibration with recording for a few days en compare it to the meter I am afraid.

For those interested how I did it some pictures.
I glued a high intensity white LED in an old knob. Aimed it from the right side at the spinning disk. Then placed a RFXCOM photosensor at the front, exactly at the spot of the reflection and voila, there was my (low budget) puls counter.

After some more studying with more light, I found that the disks are on the same spindel. The bottom one has 10 pulses versus the top one.

It looks like the top disks spins with 0,01Kwh, meaning the bottom one 0,001 or 1W/h

Post by **Bwired** » Sun May 17, 2009 12:36 pm

That's what I mean, start storing the pulses and compare it with the upper counter over a period of time.

Post by **Bastiaan** » Sun May 17, 2009 1:00 pm

I got the answer from this forum: http://www.circuitsonline.net/forum/ On the meter there is a text: C=120 meaning 120 turns for 1Kwh, the disk below is just 10:1 so indeed I get 1200 pulse per Kwh.

Post by **MindBender** » Sun May 17, 2009 1:00 pm

That's pretty nifty! I have always thought it would be very difficult to get the offset and gain right. Does it still work if you open the closet door, switch on the light, etc?

You may consider using a blue LED and blue light sensor: That way the contrast between the red spot and the rest of the dial will be bigger.

Post by **Bastiaan** » Sun May 17, 2009 1:24 pm

Yes everything works fine even when I open the doors. The contrast is high because I found an angle that works like a mirror. I haven't adjusted anything within RFXmeter yet. The LED uses 20mA from a 12v source I had nearby. If anybody is interested I can make some detailed pictures and explanation. The LED can be taken of with a click system so in case I want to change or experiment I don't need to undo the double side tape. Blue LEDs would make the contrast a bit higher but their output is lower. I did experiment with several colors and strengths but this was working fine.

Post by **esschenk** » Sun May 17, 2009 2:01 pm

Hello,

I want to buy within 2 weeks also my rfxmeter
So that I can read my meter witch spindle
If can post some pictures how you have made this
Maybe its helps my setup

Thanks

Ed

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Post by **Bastiaan** » Sun May 17, 2009 3:08 pm

It started as a little test, so I used what was near my workbench.

I found a knob that is normally use on a potmeter but this one was missing the interior.
It also had a nice plate that would give it a surface to tape and remove. The dialplate fits with four pins in the knob.

I took a 5mm extra bright white LED, I still had from samples, calculate the resistor and soldered the resistor on the LED, attached wired and protective plastic (krimpkous). Than place it in the knob with the LED lens almost out on the bottom and glued it with hot melt together.
Double side foam tape on the dial and then off for testing.
I found that the best position was for the LED set almost on the corner. Easy to see when you stand in front of the meter, where you get the best reflection. Than mark that LED position, take the tape plastic of and fix the assembly in the right place.
Then you can get the RFXphoto sensor and hold it more or less at the same hight, when you angle it a bit, you can see the LED light projected on it and then it is also a matter of marking and glueing.
I didn't needed to adjust anything in the RFXmeter. But I varied the LED current to see what was an optimum between power use and still getting a reading.