Hi all,
on completing a harmonics study on the LV side of a newly installed plant we now what to work out what harmonics levels are present on the HV side (both current, voltage and THD). the customer has their own transformer so they are only interested in what harmonics are present on the HV...
Hi, a few general questions on source impedance:
1. Why is mains a low source impedance?
2. Why are generators a high source of impedance?
3. and how does this high source impedance result in higher voltage waveform distortion where harmonics are concerned?
Thanks for your help in advance...
We have a flowmeter that has the transducer on the end of the probe and is therefore installed at the application point on the air vent pipe. these pipes are at high level and not easily accessible which is a problem for servicing and calibration. does anyone on here know of an instrument...
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...
Folks,
Our company is looking into getting a more intelligent electrical design software package than the one we are using. We’re trying to reduce the human error factors! Say we had to add an extra wire or relay to our motor control drawing, we might forget to number it, or have multiple...
Evening all. The new G5/4 regulation requires new (and possibly existing?) plant to comply within harmonic limits. At the design stage, you are required to forecast the harmonic levels the plant will generate. Now there seem to be a couple of companies offering to do this for you (at a tidy...
I’ve a few questions here!
Do the new G5/4 requirements apply to generators? Different companies can perform calculations to inform you what size and type of filter you require for your plant to be G5/4 compliant but sometimes these calculations do not take into account the situation when the...
Evening all,
I’ve a query regarding the use/need for de-tuned capacitors. Plant majority is VSD and there is an active harmonic filtering section to comply with G5/4. Now because we have the harmonic filter, we need de-tuned capacitors in our PFC section. I know it’s something to do with...
Reading up on electrical machine design it seems most if not all designers used permeance in their calculations. Is there any reason why they don’t use reluctance? I’m assuming there are pros and cons for both, theoretically, mathematically, etc. Anyone here care to divulge on both sides of...
Having difficulty understanding a bit of machine terminology and I’m hoping you chaps might be able to help…
The main field of an alternator can be thought of as a single phase winding, producing one field travelling in one direction and another field travelling in the opposite direction...
Hi there,
Anyone on here point me in the direction to a good book/paper on permeance in salient pole synchronous machines? Found a paper by Chen, Iiaogang that looks like it might have all the answers, however it’s in Chinese! Any help much appreciated. Thanks.
Hi all,
I’ve been using software for the generation and solution of electromagnetic finite element models for a while now. Since the software is in the form of a very handy user interface I was never really bothered as to how the ‘black box’ actually worked. I’m now interested in the...
