- Sun Jul 03, 2011 4:57 pm
#129659
I have a few questions on the SEN-10341 30A current sensor. http://www.sparkfun.com/products/10341
I have received two units and started to experiment with them. My overall goal is to instrument my home breaker panel to monitor energy usage on each branch. Similar to thread viewtopic.php?f=14&t=28775&p=129410
Q1) My units did not come with a 3.5mm stereo male phone plug but rather 3.5mm mono. Not a big issue, but did other purchasers have the same issue? Just a little bit worried about counterfeit parts. My electrical inspector demands UL listed parts in the breaker box. I do not want my house to burn down (go figure...)
Q2) The comments on the product page indicate that the transfer function is 1V out at 30Amps. From experience I do not think this is the case. A 60W light bulb at 120Vrms should draw 0.5Amps RMS or 0.71 amps peak to peak. In this condition, the CT generates about 36mv making the transfer function 50mv per amp. Can anyone confirm?
Observations:
It has been a fascinating experience looking at the CT output for various items I have monitored. A 60W bulb is a nice clean sinusoid (if you filter the fuzz of the signal). My LeCroy scope pulls current in a very strange way. It goes sinusoidal for about 1/3 of the half wave and them jumps up in a spike. My hot air gun on low only consumes current on 1/2 the cycle. On high it pulls current for the whole wave. And I will not even talk about my bench grinder!
My original hope to simply rectify and low pass filter the output to get a good idea of power consumptions has been dashed. If all my appliances are as ill behaved as my scope and hot air gun, I will have to sample at a high rate and compute the RMS value. Grrr. Need to pull out my copy of "IC OP AMP Cookbook" and look for an RMS circuit.
I have received two units and started to experiment with them. My overall goal is to instrument my home breaker panel to monitor energy usage on each branch. Similar to thread viewtopic.php?f=14&t=28775&p=129410
Q1) My units did not come with a 3.5mm stereo male phone plug but rather 3.5mm mono. Not a big issue, but did other purchasers have the same issue? Just a little bit worried about counterfeit parts. My electrical inspector demands UL listed parts in the breaker box. I do not want my house to burn down (go figure...)
Q2) The comments on the product page indicate that the transfer function is 1V out at 30Amps. From experience I do not think this is the case. A 60W light bulb at 120Vrms should draw 0.5Amps RMS or 0.71 amps peak to peak. In this condition, the CT generates about 36mv making the transfer function 50mv per amp. Can anyone confirm?
Observations:
It has been a fascinating experience looking at the CT output for various items I have monitored. A 60W bulb is a nice clean sinusoid (if you filter the fuzz of the signal). My LeCroy scope pulls current in a very strange way. It goes sinusoidal for about 1/3 of the half wave and them jumps up in a spike. My hot air gun on low only consumes current on 1/2 the cycle. On high it pulls current for the whole wave. And I will not even talk about my bench grinder!
My original hope to simply rectify and low pass filter the output to get a good idea of power consumptions has been dashed. If all my appliances are as ill behaved as my scope and hot air gun, I will have to sample at a high rate and compute the RMS value. Grrr. Need to pull out my copy of "IC OP AMP Cookbook" and look for an RMS circuit.