Very hot cables in our PFC unit
Very hot cables in our PFC unit
(OP)
We installed a PFC unit at one of our sites as well as an active filtering unit. Now because our capacitors were not de-tuned, the PFC unit would not operate as required (or so we were told). We have now installed series inductors to detune the unit, however the cables coming from the contactor to the reactors/capacitors are very very hot! Now the cables were fine before installing the reactors, but now the cables are roasting! Has anyone on here encountered this problem before and how it may be cured?
Thanks in advance
Thanks in advance






RE: Very hot cables in our PFC unit
Gunnar Englund
www.gke.org
RE: Very hot cables in our PFC unit
Thanks for your help. It's off at present, and we're heading to the site early next week so we'll check the voltages then.
RE: Very hot cables in our PFC unit
I suspect that the first issue was that a problem with the PFC was mis-diagnosed as a "Tuning" problem. It sounds like the second problem may have been calculating a reactor value to achieve resonance rather than to avoid resonance.
It will probably be useful to skogsgurra if you describe the order of connection of the filtering unit, the power factor correcting capacitors and the sensing point for the PFC unit.
respectfully
RE: Very hot cables in our PFC unit
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RE: Very hot cables in our PFC unit
RE: Very hot cables in our PFC unit
RE: Very hot cables in our PFC unit
One thing to be careful of, is the detuning reactors do give off a lot of heat compared to the capacitors on their own. If you have a lot of harmonics on the supply, then you should use very good ventillation in the enclosure. It is common to add thermostatic control of ventillation fans to keep things cool.
Best regards,
Mark Empson
http://www.lmphotonics.com
RE: Very hot cables in our PFC unit
RE: Very hot cables in our PFC unit
Thanks for your help.
RE: Very hot cables in our PFC unit
You need to get an idea of the power dissipated in the enclosure by the reactors etc and from that, you can calculate the air flow required to achieve your desired temperature rise.
I use some software that I wrote to help with the airflow calcs, but you still need to determine the power dissipation.
You can download the software from my web site.
Best regards,
Mark Empson
http://www.lmphotonics.com
RE: Very hot cables in our PFC unit
John
RE: Very hot cables in our PFC unit
Thanks,
subra