AWS IoT Current Sensor reporting 0 current on 240v dryer

Hardware
1

Hello, I have an AWS IoT Current Sensor, Model PR58-3_AWS, configured and sending messages to a topic in AWS IoT. I have the current sensor clamped around a 240v dryer power cord. The current value in the received messages remains 0 regardless of whether the dryer is operating or not.

2

is the current clamp wrapped around both wires ( live and natural) ?
if yes, then it will read zero. because emf is getting canceled.
it should be wrapped around only one wire.

3

Thanks for your reply. That seems obvious now that you say it. I moved the clamp so it’s only wrapped around the live wire and I get current readings now most of the time. Some of the time when the dryer is running the current reads 0. I’m wondering if this is detecting when the heating element turns on and off and when it’s off and just the fan and tumbler motor are running the current draw is less than 1.5A.

4

It could be zero in between

  1. Heater should be going on off to maintain a fixed temperature
  2. Total power consumption is lower than 1.5 A
5

Hi Bhaskar, thanks for confirming what I was suspecting.

Is there a way to calibrate the sensor to detect current less than 1.5A or any other way to set it up so that current less than 1.5A can be detected?

6

Hi Jason,
easy fix – wrap the wire around the sensor like 5 times and then divide the current reading by 5.

Thanks

7

Thanks. I wanted to report back here in case it helps anyone in the future. I did try wrapping the wire around the sensor multiple times which did multiply the current but I still observed it going to 0, presumably when the heating element turned off. I then had the thought, what if the dryer was wired such that the tumbler motor and blower were on the 2nd live wire and the heating element was on the first. I moved the sensor to the 2nd live wire and the current is now detected the entire time the dryer is running but at a lower constant level. As I only needed to be able to detect the on/off state of the dryer this works fine for my purpose. If I was trying to detect the total current draw of the dryer as a whole I’m not sure how that could be accomplished.