Neelis, I apologize it took me so long to get back to you and though I suspect you had to solve your issue by now I will post what I did.
The system I was studying had no neutral connection between the VFD and the switchgear. As a result, I do not know how the triplen harmonics were travelling...
If you run the fan at a constant speed the VFD will increase your energy use compared to a softstart or across the line starter with a resheave.
The VFD will only save you money if there are times you need to turn down the fan speed.
The VFD will increase your energy usage because it is...
I have been going back and forth with the software company trying to determine their take on this situation and what they have implemented.
It makes sense to me that if there is no neutral there should be no path back to the transformer for the triplen harmonics. What happens to them isn't as...
Thanks for the great responses!
jghrist - We too were quite surprised at the level of harmonics below the 23rd that were collected during the manufacturer testing. We went several rounds with the manufacturer and they state it is representative of their drives so it is what we have to work...
Hello,
I am performing a harmonic analysis of a 24 pulse 4160 V VFD. This VFD is replacing existing VFDs of the same size and will be connected to an existing system which has delta-y transformers with neutral grounding resistors. This 24 pulse drive has significant 3rd harmonics as determined...
