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Is this a homework/coursework problem?

Its a project that I'm working on and the objective is to calculate the power factor

 

What values of burden resistor are you using?
How much current are you running through the ZMPT101B.
Did you bias the outputs at half supply?

I'm not using a burden resistor, if this is the case, how may I calculate its value?
I'm supply 120V to ZMPT101B
I didn't bias the output

 

I'm not using a burden resistor, if this is the case, how may I calculate its value?
I'm supply 120V to ZMPT101B
I didn't bias the output

Here is the ZMPT101B datasheet and a few split-core current transformers.
The ZMPT101b isn't quite 100% efficient but if you use the next highest E24 value you get about the right answer. You will have to calibrate it for optimum accuracy.

 

Its a project that I'm working on and the objective is to calculate the power factor

Is the project for academic credit?

 

What values of burden resistor are you using?
How much current are you running through the ZMPT101B.
Did you bias the outputs at half supply?

Here is the ZMPT101B datasheet and a few split-core current transformers.
The ZMPT101b isn't quite 100% efficient but if you use the next highest E24 value you get about the right answer. You will have to calibrate it for optimum accuracy.

Thanks for providing links for datasheets. I'm referring for these:
VT: https://innovatorsguru.com/wp-content/uploads/2019/02/ZMPT101B.pdf
CT: https://cdn.shopifycdn.net/s/files/1/2723/6858/files/HSTS016L_2.5V_0.625V_5V.pdf?v=1669012972

The CT that I'm using has a rated output 2.5 +/- 0.625 V, so I don't need a burden resistor. But I still need a burden resistor for the VT since its output signal is current not voltage.
looking for how to pick the Rb size.

 

CT: https://cdn.shopifycdn.net/s/files/1/2723/6858/files/HSTS016L_2.5V_0.625V_5V.pdf?v=1669012972

That's a Hall-effect device.
When you said that they output was stuck at 2.5V. Did you measure it with an oscilloscope?

 

That's a Hall-effect device.
When you said that they output was stuck at 2.5V. Did you measure it with an oscilloscope?

I measure it with a multimeter.

 

This question is for moderation purposes, please answer.

@OthmanMD is this for academic credit?

 

I measure it with a multimeter.

In which case, you won't notice the AC signal superimposed on it. It is probably functioning correctly.
If you want more detailed help, you should answer @Ya’akov 's question.

 

This question is for moderation purposes, please answer.

@OthmanMD is this for academic credit?

Yes, this is for an academic project as part of my coursework. However, I'm only seeking guidance and clarification on certain aspects of the project. I'm not looking for someone to do the work for me, but rather to understand specific concepts or troubleshoot issues I've encountered.

 

In which case, you won't notice the AC signal superimposed on it. It is probably functioning correctly.
If you want more detailed help, you should answer @Ya’akov 's question.

Do you suggest using an oscilloscope instead of a multimeter?

 

Do you suggest using an oscilloscope instead of a multimeter?

You won't see a 50Hz signal on a multimeter!

 

Yes, this is for an academic project as part of my coursework. However, I'm only seeking guidance and clarification on certain aspects of the project. I'm not looking for someone to do the work for me, but rather to understand specific concepts or troubleshoot issues I've encountered.

Thank you for answering. Your thread has been moved to the Homework Help forum. Your expectations for guidance and clarification are fine, in fact AAC rules limit members to providing such assistance. For that reason all posts involving questions for which the poster will recieve academic credit for solving are required to be posted in this forum.

In the future, please post them directly to Homework Help. Thank you.

 

Looking at the datasheet of your current transducer, what output voltage would you expect at the positive and negative peaks of your current waveform?

 

You won't see a 50Hz signal on a multimeter!

Oh yes this is true.

Looking at the datasheet of your current transducer, what output voltage would you expect at the positive and negative peaks of your current waveform?

The offset is 2.5 V, which is the output when there is zero current flowing. With current flowing in the forward direction, the expected output voltage is 2.5+0.625. With current flowing in reverse direction the expected output is 2.5 - 0.625 V

 

Oh yes this is true.


The offset is 2.5 V, which is the output when there is zero current flowing. With current flowing in the forward direction, the expected output voltage is 2.5+0.625. With current flowing in reverse direction the expected output is 2.5 - 0.625 V

And how would your ADC read that?

 

And how would your ADC read that?

ADC will read the V-out terminal of the sensors

 

ADC will read the V-out terminal of the sensors

And then how do you translate that into a number which represents the current?

 

Hey everyone!
I want to measure Appearant Power (S), Real Power (P), and Reactive Power (Q).
My load is Heat Pump Water Heater (HPWT) with input voltage of 240V.
Currently I have voltage and current transducer implemented in my circuit.

The output singals of both transducers are DC, so what are the possible ways to measure the phase angle and power factor besides the S, P, and Q?

Thanks,

Not sure if this has been mentioned yet, but probably using a microcontroller is a good way to go with this.
Using that you can calculate anything you need after making some measurements of the current and voltage. You can also use it to drive a display and show the readings in near real time.

To measure any of those quantities you have to be able to measure the current wave and the voltage wave. You need to measure the amplitude, but also the zero crossings. The zero crossings will tell you what the phase angle is.
You also have to deal with a little noise so you may have to use averages rather than single measurements. If you average over many readings you can usually get past the noise.

You also have to check the finished system to make sure it can do the job right and is reliable. For that you would normally use an oscilloscope, but not sure if you have one of those yet.

 

Not sure if this has been mentioned yet, but probably using a microcontroller is a good way to go with this.
Using that you can calculate anything you need after making some measurements of the current and voltage. You can also use it to drive a display and show the readings in near real time.

To measure any of those quantities you have to be able to measure the current wave and the voltage wave. You need to measure the amplitude, but also the zero crossings. The zero crossings will tell you what the phase angle is.
You also have to deal with a little noise so you may have to use averages rather than single measurements. If you average over many readings you can usually get past the noise.

You also have to check the finished system to make sure it can do the job right and is reliable. For that you would normally use an oscilloscope, but not sure if you have one of those yet.

He has a Raspberry Pi and a MCP3008 (Post #5)

Timing the zero-crossings will probably work in his case because the load is an induction motor, but if the current waveform is non-sinusoidal it won't.
Dividing the real power by the VA will work in all circumstances. A phase angle can be computed by taking the inverse cosine, but it will only be meaningful if the current waveform is a sinusoid.