- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Just checking to see if anyone else has run into this. I have a customer who has a 200HP VFD on a submersible pump. 1/4 mile away is another station that has pressure transducers. Whenever the VFD is running, the pressure transducers go haywire. It's been thoroughly vetted, the link is definitely there. No VFD, no interference; VFD running, squirrely transducers.
First course of action will be ferrite cores on the transducer wires, then EMI/RFI filters on the line side, but the only connection is the utility; two separate services / transformers 1/4 mile apart. there are no other wires, pipes or conduits connecting the two sites (according to them). To me that seems implausible, but that is the cheaper filter. Final action will be to suggest Sine Wave Filters on the output of the VFD, but those are going to be expensive.
What I want to know is if anyone has experienced something similar due to the fact that the pump cables for submersibles are almost always unshielded. I've had all sorts of issues with unshielded cables topside, but have always assumed that with the sub cables being under ground, no harm/ no foul. But this has me rethinking that. I've been taught that radio waves don't penetrate the earth; too dense. But someone once told me that FM does pass through hills and mountains if the distance is short. I have no confirmation of that, but this situation has me wondering if that might be true.
First course of action will be ferrite cores on the transducer wires, then EMI/RFI filters on the line side, but the only connection is the utility; two separate services / transformers 1/4 mile apart. there are no other wires, pipes or conduits connecting the two sites (according to them). To me that seems implausible, but that is the cheaper filter. Final action will be to suggest Sine Wave Filters on the output of the VFD, but those are going to be expensive.
What I want to know is if anyone has experienced something similar due to the fact that the pump cables for submersibles are almost always unshielded. I've had all sorts of issues with unshielded cables topside, but have always assumed that with the sub cables being under ground, no harm/ no foul. But this has me rethinking that. I've been taught that radio waves don't penetrate the earth; too dense. But someone once told me that FM does pass through hills and mountains if the distance is short. I have no confirmation of that, but this situation has me wondering if that might be true.