How to measure 50 V, 80A DC voltage using Arduino

Using Arduino Project Guidance
1

I need to measure DC voltage whose maximum voltage can go to 50-60 V. I could simply use voltage divider circuit but the problem is that the motor connected to supply can draw around 80 amps of current (this is the max current). So the resistors in voltage divider wont sustain such high current. Morever, I dont think the voltage sensor will be helpful as well.
So what should i do?? An ideas?/

2

Hi, @purnasish

The motor current will not be flowing through the potential divider, so you do not have to worry about the motor current damaging the resistors.

Can you post a diagram of how you have your motor and divider wired?

Does the motor need to change direction?

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

1 Like
3

Ahh yes! The current thing sorted out. Thanks @TomGeorge .

Just asking, to measure the voltage across the motor, i am thinking to use combination of three 25V rating voltage sensor in series with the motor in parallel. Is this the most efficient way or should I try something else?

4

Which Arduino are you using? If the motor voltage is 60, what voltage do you want on the Arduino input pin?

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@JCA34F i am using arduino mega.I am thinking to take 5v on the input pin. I will be using 5v arduino supply pin to power modules like lcd display, acs 712 current sensor, HX711 load cell.

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Why would you need 3?

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voltage can go upto 60 V

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Here's a 60 to 4.56V divider:

Scheme-it-export-New-Project-2024-01-08-03-11

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That is why you need a voltage divider.
Two resisors in series...
100 kOhm and 5.6 kOhm.
Then measure voltage over 5.6 kOhm.
Also add 100 nF capacitor over 5.6 kOhm resistor to get rid of voltage spikes from the motor.

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@JCA34F beat me! I recommend starting with 100 kOhm, as we do not know how big the voltage spikes from the motor are....

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Hi, @purnasish

Some important questions;

  1. Is you motor connected to a motor controller.
  2. Does your motor run in both directions?
  3. What is the motor assembly doing?

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

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@TomGeorge

  1. Yes motor controller is being used
  2. no
  3. moter is used to power a generator
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Can you post a diagram showing the motor and controller connections.
I'm worried the that the motor input voltage will not be with respect to earth.

What is the supply to the motor controller?
Can you please post a link to data/specs of the motor controller?

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

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@TomGeorge @JCA34F @build_1971 I think i misguided you guys a bit. i am measuring the voltage across the supply voltage only, not across the motor. I am going to use three 25v voltage sensor directly. Thank you for your time.

15

That will not work.
Please post a diagram showing how you would connect them and a link to specs/data.

Can you please tell us your electronics, programming, arduino, hardware experience?

Tom... :grinning: :+1: :coffee: :australia:

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

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17047039816928740111084701621074
170470398169287401110847016210741920×1440 93.6 KB

This the the rough circuit diagram. @TomGeorge

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Can you tell us the difference?
The schematic given would work for measuring power supply voltage up to 60 V...

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I think you do not really understand the concept of voltage divider.
A voltage sensor is a rather expensive resistor...

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Do you mean 3 of these?

https://m.media-amazon.com/images/I/61+AXXMKOGL.AC_SL1001.jpg

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Yes