How to measure stator current in 1ph induction motor

Using Arduino Project Guidance
21

We have the 6205 rs bearing, and we're trying to study the correlation of stator current signals and bearing faults in induction motors. as per our motor, we wont be using any load, so its a constant no load condition. Should we add load to our motor, so we canhave this kind of raw signal in our current reading?
image

22

Hi,
Can you please post a bigger image with more resolution, so we can see your raw signal?

Have you actually looked at the current with a scope?

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

23

i cant really upload a higher reso for that image but the raw signal should look like this
image

24

this is the raw current signal that we collected. its current wrt time (ms):
image

but this is our expected output:
image

do u guys know how can we come up with our expected output?

25

Hi,
What would you expect on the sinewave of the motor current to indicate bearing faults?

I doubt the UNO would give you the time resolution to see any noise from a failing bearing.

Can I suggest you get a motor, damage the bearing or fill it with sand/iron filings to first see what signal you have to measure.

Tom... :smiley: :+1: :coffee: :australia:

26

my expected output should be in sinewave form as per the past studies but the current signal that we're collecting is not like that at all. as of the moment we're just collecting our data from the healthy motor, no indicated faults yet. so can u guys suggest ways on how can we come up with a sine wave form current signal in arduino uno? thank you.

27

Hi,
We need to see your code.
The output trace looks like it is reading average, rms, or peak and not instantaneous.

The fact that there are 2253 between readings probably means your code is doing a lot more than reading analog and outputting.

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

28

this is the code

image
image1920×1080 116 KB

29

To add code please click this link;

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

30

Hi,
What does PZEM have to do with 712 sensor?

Can you please post an image(s) of your project?

Can we please have a circuit diagram?
An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.

Is this a school/college/university project?

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

31

we changed the sensor to pzem-004t and this is the wiring now

image
image710×462 120 KB

32

this is the type written code:

#include <PZEM004Tv30.h>
#include <SoftwareSerial.h>

SoftwareSerial pzemSWSerial(9, 10);
PZEM004Tv30 pzem(pzemSWSerial);

void setup() {
/* Debugging serial */
Serial.begin(115200);
}

void loop() {
float current = pzem.current();

Serial.println(current);

}

33 
#include <PZEM004Tv30.h>
#include <SoftwareSerial.h>

SoftwareSerial pzemSWSerial(9, 10);
PZEM004Tv30 pzem(pzemSWSerial);

void setup() {
/* Debugging serial */
Serial.begin(115200);
}

void loop() {
float current = pzem.current();

Serial.println(current);

}

You will find that the PZE is a home energy monitor and supplies the basic RMS and power factor information.

You would have a better signal with the 712.

What was your 712 code and schematic?

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:
PS, Please tell us when you do major hardware changes.

34

so its not recommended for motor current signal analysis?

35

IF that motor in the picture is like your motor, it is a 2 phase motor with a capacitor producing the second phase. How about a picture of your actual motor.

36

our motor is just a single phase 1.5ph ac motor. its the yc90l-4 type.

37

When I Googled that code, it returns a picture of a motor with 2 capacitors. That means the motor is actually 3-phase with each capacitor providing a different phase. You may be providing single phase power to the motor, but is converts it.
The difference is the current to the motor will be a combination of the currents for all three phases.
Get a real single phase motor with NO capacitors.

38

hi guys, im new here and i am hoping you guys can help me with my project. i am currently conducting a study about bearing fault diagnosis using current signals. we just started the data collection but the current signal that I am getting is kinda far from the expected output as per the past studies of this project.

this is the collected current data (current wrt time in ms):
image

while this should be the expected output:
image

btw we are using arduino uno with pzem-004t to collect current signals from our 1.5hp single phase ac induction motor. thank you for your help in advance.

39

Once working for SKF for a few years I remember they listened to the frequency from the besring, picked up by microphones, vibration sensors....
Have You looked AC current sensor containing some processing?
You know You can't send a negative signal into an Arduino?

40

Looks like one sample every 2.25 seconds.

That looks like 1400 samples per second on a 50 Hz signal.

You need to sample faster!