Sine Wave Tracking

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growerdick

Joined Oct 8, 2012
14
I need to track the sine wave of a 240vac line. I want to isolate the ADC completely from the 240vac. I visualize a bridge and divider into an specialized optical isolator with data and power on the other side to a remote micro and ADC. Does anyone have any recommendations for parts? I don’t want to reinvent the wheel, are there already devices available? Thanks.
 

Reloadron

Joined Jan 15, 2015
5,721
You can try a Google of ZMPT101B (AC Output Voltage Sensor Active Single Phase Voltage Transformer Board Module for Arduino Mega ZMPT101B 2mA). While they mention Arduino the module is useable with any uC having ADC capabilities.

Ron
 

BobTPH

Joined Jun 5, 2013
2,745
What do you mean by track? Do you need to sample the voltage throughout the cycle, or just sync to the frequency? If the latter, a zero cross detector is what you need.

Bob
 

Ian0

Joined Aug 7, 2020
1,158
If you need the phase to be correct use one of these:
https://uk.rs-online.com/web/p/toroidal-transformers/2238982/
not one of these:
https://uk.rs-online.com/web/p/pcb-transformers/0504397/

The split bobbin transformers have much lower L(mag) and much higher L(leak).
L(mag) is 12.6H for the split bobbin and 1600H for the toroid.
L(leak) is about 1H for both of them.
The low value of L(mag) gives a phase advance due to a highpass LR filter being formed.

If you are monitoring 3-phase for a missing neutral, you'll need a transformer with a 400V primary. A standard 230V transformer will saturate and burn out the primary if that happens.
 
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