Nola Type Energy Savers And Harmonics

Hi all, has anyone had a chance to study the harmonic caractaristics of these devices? I would be interested in any experiences or measurements.

Thanks

Ken

Displacement Vs Distortion

Hi all, if we have a supply that is known to have significant current distortion (~ 25%), but also a large amount of inductive loads, is there any simple method of calculating the proportional effect on the total power factor. The reason for the calculation is that if the utility company is charging for a pf of <0.95 we need to know if we can improve the pf sufficiently using capacitors ( with blocking reactors) which is the less expensive option, or whether the correction requires the more expensive hamonic filtering. Generally the payback for standard capacitive correction is acceptable but hamonic filtering is not.

Again, all help appreciated.

Ken

Static Correction Of Screw Refrigeration Compressors

Hi All, when considering static compensation for a screw compressor what is the best method for calculating capacitor size? As the load varies considerably as the machine loads and unloads I would imagine that care must be taken to avoid any resonance problems. Also the use of a seperate contactor seems to be essential as often when the machine cycles off the compressor will reverse direction for a short period due to the pressure equalising in the system.

All help appreciated.
Kens

Harmonics, Power Factor

Heres a link for some free software that shows various pf and harmonic waveforms etc
http://www.powerstandards.com/PQTeachingToyIndex.htm
Ken

Electronic Versus Contactor Switching

Could someone please give me an unbiased opinion on the advantages of electronic switching of power factor correction capacitors compared to the cheaper option of contactor control.
Best regards
Ken